Remove test_unsupported_default_store
Remove test_unsupported_default_store

Config option 'default_store' in group 'glance_store' only allows value
in [file, filesystem, http, https, swift, swift+http, swift+https,
swift+config, rbd, sheepdog, cinder, vsphere] due to the parameter
choices, oslo.config will ensure that, other value will lead ValueError.
So don't need test this case.

Related-Bug: #1517839
Change-Id: I3459a8e9f07ed9464073133931fadc77f8186602

openstack/glance,rajalokan/glance,rajalokan/glance,openstack/glance,openstack/glance