ImageService v2: Fixing Create Properties (#264)

* Fix Creating Image Properties

The combination of JSON tags were not rendering the JSON body
correctly and causing a 400 error by the API.

* ImageService v2 Acceptance Tests

* unit tests
diff --git a/openstack/imageservice/v2/images/testing/requests_test.go b/openstack/imageservice/v2/images/testing/requests_test.go
index fdd8402..0371e4c 100644
--- a/openstack/imageservice/v2/images/testing/requests_test.go
+++ b/openstack/imageservice/v2/images/testing/requests_test.go
@@ -69,6 +69,9 @@
 	actualImage, err := images.Create(fakeclient.ServiceClient(), images.CreateOpts{
 		ID:   id,
 		Name: name,
+		Properties: map[string]string{
+			"architecture": "x86_64",
+		},
 		Tags: []string{"ubuntu", "quantal"},
 	}).Extract()