Refactor OpenStack services to use default OkCodes
diff --git a/openstack/networking/v2/subnets/requests.go b/openstack/networking/v2/subnets/requests.go
index 63ac290..f66a6ac 100644
--- a/openstack/networking/v2/subnets/requests.go
+++ b/openstack/networking/v2/subnets/requests.go
@@ -80,7 +80,6 @@
 	var res GetResult
 	_, res.Err = c.Request("GET", getURL(c, id), gophercloud.RequestOpts{
 		JSONResponse: &res.Body,
-		OkCodes:      []int{200},
 	})
 	return res
 }
@@ -174,7 +173,6 @@
 	_, res.Err = c.Request("POST", createURL(c), gophercloud.RequestOpts{
 		JSONBody:     &reqBody,
 		JSONResponse: &res.Body,
-		OkCodes:      []int{201},
 	})
 
 	return res
@@ -241,8 +239,6 @@
 // Delete accepts a unique ID and deletes the subnet associated with it.
 func Delete(c *gophercloud.ServiceClient, id string) DeleteResult {
 	var res DeleteResult
-	_, res.Err = c.Request("DELETE", deleteURL(c, id), gophercloud.RequestOpts{
-		OkCodes: []int{204},
-	})
+	_, res.Err = c.Request("DELETE", deleteURL(c, id), gophercloud.RequestOpts{})
 	return res
 }