Fix fail logic for server of another tenant test

This commit removes the try, finally logic from
test_delete_a_server_of_another_tenant() If the create_server() call
failed then the delete in the finally block would still run. This
would cause the test to error out masking the real reason for the
failure. This commit corrects the behavior by removing the delete and
the try, finally from the test. The base class will properly handle
the cleanup of the created server on class tear down so this delete
wasn't even necessary.

Change-Id: I6ee7c74122b4c88416672e5f0d3f3fb2bd71ab69
1 file changed