Add check for image_locations table
Add check for image_locations table

This commit adds a check for the image_locations table to the
_assert_tables method in TestGlanceManage. When migration 018
was added in change: I1536c9276bc807aac26849e37556b465e8b5c9eb
a new image locations table was created, but didn't update the
functional tests to check that it had been created.

Change-Id: If76702f623e201505c62d05e245003e3783d8574

akash1808/glance,dims/glance,jumpstarter-io/glance,redhat-openstack/glance,takeshineshiro/glance,citrix-openstack-build/glance,saeki-masaki/glance,tanglei528/glance,paramite/glance,scripnichenko/glance,rickerc/glance_audit,dims/glance,ntt-sic/glance,ntt-sic/glance,vuntz/glance,ozamiatin/glance,JioCloud/glance,klmitch/glance,SUSE-Cloud/glance,rajalokan/glance,rickerc/glance_audit,vuntz/glance,darren-wang/gl,JioCloud/glance,paramite/glance,SUSE-Cloud/glance,sigmavirus24/glance,klmitch/glance,jumpstarter-io/glance,openstack/glance,sigmavirus24/glance,openstack/glance,cloudbau/glance,stevelle/glance,rajalokan/glance,takeshineshiro/glance,darren-wang/gl,akash1808/glance,cloudbau/glance,redhat-openstack/glance,kfwang/Glance-OVA-OVF,kfwang/Glance-OVA-OVF,scripnichenko/glance,tanglei528/glance,wkoathp/glance,citrix-openstack-build/glance,stevelle/glance,saeki-masaki/glance,wkoathp/glance,ozamiatin/glance,openstack/glance