Remove caching config from test_image
Remove caching config from test_image

The caching config isn't the actual config we need. Remove it so that
the refactor can be cleaner.

Change-Id: I6bbc17d78e49c98394e8f391192c2dbc35889ae8

dtroyer/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,openstack/python-openstacksdk,openstack/python-openstacksdk,stackforge/python-openstacksdk,openstack-infra/shade,openstack-infra/shade