The test added in I3e238b6a97769cf0a352f11e718d5d73eebcfa8a
will fail if the corresponding backend is not actually
available, because the resources dictionary will be empty.
Add a skip mechanism based on whether or not the DatabaseResource
has backend available or not.
Change-Id: I0ecb4a7ba6531b50c9c3abc6c9c8564b0df54f61