Use version negotiation in openstack.NewClient().
diff --git a/openstack/identity/v3/client.go b/openstack/identity/v3/client.go
index 5f25ee6..984d03e 100644
--- a/openstack/identity/v3/client.go
+++ b/openstack/identity/v3/client.go
@@ -24,7 +24,7 @@
 	return &Client{
 		ServiceClient: gophercloud.ServiceClient{
 			ProviderClient: *provider,
-			Endpoint:       provider.IdentityEndpoint + "v3/",
+			Endpoint:       provider.IdentityEndpoint,
 		},
 	}
 }