Correctly name the functional TestImage class
Correctly name the functional TestImage class

This seems like a copy-pasta that got overlooked, the TestImage class
should not be named TestCompute.

Change-Id: I00e9d651936f1aacfece5f461b41c43573830715

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