Added functionality for updating and resetting compute quotas. (#214)

* Added functionality for updating and resetting compute quotas.
Unit and acceptance tests added.

* Forgot to add my latest changes.
Modified acceptance test to better find the tenant-id

* Improved test coverage.
And fixed a bug while doing this.

* Moved FillFromQuotaSet to acceptance test package
Refractored ToComputeQuotaUpdateMap()
diff --git a/acceptance/openstack/compute/v2/compute.go b/acceptance/openstack/compute/v2/compute.go
index 3392c2e..97d61f6 100644
--- a/acceptance/openstack/compute/v2/compute.go
+++ b/acceptance/openstack/compute/v2/compute.go
@@ -710,6 +710,24 @@
 	})
 }
 
+//Convenience method to fill an QuotaSet-UpdateOpts-struct from a QuotaSet-struct
+func  FillUpdateOptsFromQuotaSet(src quotasets.QuotaSet,dest *quotasets.UpdateOpts) {
+	dest.FixedIps = &src.FixedIps
+	dest.FloatingIps = &src.FloatingIps
+	dest.InjectedFileContentBytes = &src.InjectedFileContentBytes
+	dest.InjectedFilePathBytes = &src.InjectedFilePathBytes
+	dest.InjectedFiles = &src.InjectedFiles
+	dest.KeyPairs = &src.KeyPairs
+	dest.Ram = &src.Ram
+	dest.SecurityGroupRules = &src.SecurityGroupRules
+	dest.SecurityGroups = &src.SecurityGroups
+	dest.Cores = &src.Cores
+	dest.Instances = &src.Instances
+	dest.ServerGroups = &src.ServerGroups
+	dest.ServerGroupMembers = &src.ServerGroupMembers
+	dest.MetadataItems = &src.MetadataItems
+}
+
 // PrintServer will print an instance and all of its attributes.
 func PrintServer(t *testing.T, server *servers.Server) {
 	t.Logf("ID: %s", server.ID)
diff --git a/acceptance/openstack/compute/v2/quotaset_test.go b/acceptance/openstack/compute/v2/quotaset_test.go
index d9e73e9..2fb7c99 100644
--- a/acceptance/openstack/compute/v2/quotaset_test.go
+++ b/acceptance/openstack/compute/v2/quotaset_test.go
@@ -10,6 +10,8 @@
 	"github.com/gophercloud/gophercloud/acceptance/clients"
 	"github.com/gophercloud/gophercloud/openstack/compute/v2/extensions/quotasets"
 	"github.com/gophercloud/gophercloud/openstack/identity/v2/tenants"
+	th "github.com/gophercloud/gophercloud/testhelper"
+	"os"
 )
 
 func TestQuotasetGet(t *testing.T) {
@@ -53,3 +55,131 @@
 
 	return "", fmt.Errorf("Unable to get tenant ID")
 }
+
+func getTenantIDByName(t *testing.T, client *gophercloud.ServiceClient, name string) (string, error) {
+	allPages, err := tenants.List(client, nil).AllPages()
+	if err != nil {
+		t.Fatalf("Unable to get list of tenants: %v", err)
+	}
+
+	allTenants, err := tenants.ExtractTenants(allPages)
+	if err != nil {
+		t.Fatalf("Unable to extract tenants: %v", err)
+	}
+
+	for _, tenant := range allTenants {
+		if tenant.Name == name{
+			return tenant.ID, nil
+		}
+	}
+
+	return "", fmt.Errorf("Unable to get tenant ID")
+}
+
+//What will be sent as desired Quotas to the Server
+var UpdatQuotaOpts = quotasets.UpdateOpts{
+	FixedIps:                 gophercloud.IntToPointer(10),
+	FloatingIps:              gophercloud.IntToPointer(10),
+	InjectedFileContentBytes: gophercloud.IntToPointer(10240),
+	InjectedFilePathBytes:    gophercloud.IntToPointer(255),
+	InjectedFiles:            gophercloud.IntToPointer(5),
+	KeyPairs:                 gophercloud.IntToPointer(10),
+	MetadataItems:            gophercloud.IntToPointer(128),
+	Ram:                      gophercloud.IntToPointer(20000),
+	SecurityGroupRules:       gophercloud.IntToPointer(20),
+	SecurityGroups:           gophercloud.IntToPointer(10),
+	Cores:                    gophercloud.IntToPointer(10),
+	Instances:                gophercloud.IntToPointer(4),
+	ServerGroups:             gophercloud.IntToPointer(2),
+	ServerGroupMembers:       gophercloud.IntToPointer(3),
+}
+
+//What the Server hopefully returns as the new Quotas
+var UpdatedQuotas = quotasets.QuotaSet{
+	FixedIps:                 10,
+	FloatingIps:              10,
+	InjectedFileContentBytes: 10240,
+	InjectedFilePathBytes:    255,
+	InjectedFiles:            5,
+	KeyPairs:                 10,
+	MetadataItems:            128,
+	Ram:                      20000,
+	SecurityGroupRules:       20,
+	SecurityGroups:           10,
+	Cores:                    10,
+	Instances:                4,
+	ServerGroups:             2,
+	ServerGroupMembers:       3,
+}
+
+func TestQuotasetUpdateDelete(t *testing.T) {
+	client, err := clients.NewComputeV2Client()
+	if err != nil {
+		t.Fatalf("Unable to create a compute client: %v", err)
+	}
+
+	idclient, err := clients.NewIdentityV2Client()
+	if err != nil{
+		t.Fatalf("Could not create IdentityClient to look up tenant id!")
+	}
+
+	tenantid, err := getTenantIDByName(t, idclient, os.Getenv("OS_TENANT_NAME"))
+	if err != nil{
+		t.Fatalf("Id for Tenant named '%' not found. Please set OS_TENANT_NAME appropriately", os.Getenv("OS_TENANT_NAME"))
+	}
+	
+
+	//save original quotas
+	orig, err := quotasets.Get(client,tenantid).Extract()
+	th.AssertNoErr(t,err)
+
+	//Test Update
+	res, err := quotasets.Update(client,tenantid,UpdatQuotaOpts).Extract()
+	th.AssertNoErr(t,err)
+	th.AssertEquals(t,UpdatedQuotas,*res)
+
+	//Test Delete
+	_,  err = quotasets.Delete(client,tenantid).Extract()
+	th.AssertNoErr(t,err)
+	//We dont know the default quotas, so just check if the quotas are not the same as before
+	newres, err := quotasets.Get(client,tenantid).Extract()
+	if newres == res{
+		t.Fatalf("Quotas after delete equal quotas before delete!")
+	}
+
+
+	restore := quotasets.UpdateOpts{}
+	FillUpdateOptsFromQuotaSet(*orig,&restore)
+
+	//restore original quotas
+	res, err = quotasets.Update(client,tenantid,restore).Extract()
+	th.AssertNoErr(t,err)
+
+	orig.ID = ""
+	th.AssertEquals(t,*orig,*res)
+
+}
+
+// Makes sure that the FillUpdateOptsFromQuotaSet() helper function works properly
+func TestFillFromQuotaSetHelperFunction(t *testing.T){
+	op := &quotasets.UpdateOpts{}
+	expected := `
+	{
+	"fixed_ips": 10,
+	"floating_ips": 10,
+	"injected_file_content_bytes": 10240,
+	"injected_file_path_bytes": 255,
+	"injected_files": 5,
+	"key_pairs": 10,
+	"metadata_items": 128,
+	"ram": 20000,
+	"security_group_rules": 20,
+	"security_groups": 10,
+	"cores": 10,
+	"instances": 4,
+	"server_groups": 2,
+	"server_group_members": 3
+	}`
+	FillUpdateOptsFromQuotaSet(UpdatedQuotas,op)
+	th.AssertJSONEquals(t,expected,op)
+}
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