Use FakeFlavor in TestServerCreate.
Use FakeFlavor in TestServerCreate.

Change-Id: Ib82f845258b1ad78cbc8b23d28fa42e7ccc8097a
Implements: blueprint improve-flavor-unit-test

dtroyer/python-openstackclient,BjoernT/python-openstackclient,BjoernT/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient,dtroyer/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient