added decorator-based mocks declaration to

    * test_openstack_provider_init
    * test_openstack_provider_init_no_glance
    * test_openstack_provider_init_with_invalid_conf_no_user
    * test_openstack_provider_init_with_invalid_conf_no_url
    * test_openstack_provider_init_with_invalid_conf_extra_key
    * test_openstack_provider_init_with_invalid_conf_flavor_
    * test_openstack_provider_with_valid_config
    * test_openstack_provider_with_valid_config_uuid
    * test_openstack_provider_with_valid_config_checksum

Change-Id: I1a6bcda26de03f6f0daf56dd687f857c029d6b54