Remove unused exception StorageQuotaFull
Remove unused exception StorageQuotaFull

This exception is not used in the glance_store code. Corresponding
necessary exception exists in the glance code base.

Change-Id: I12cb47f7a78ab3358381ca0dc197f997c435a6de

hmakkapati/glance_store,saeki-masaki/glance_store,jamielennox/glance_store,jamielennox/glance_store,cpallares/glance_store,openstack/glance_store,redhat-openstack/glance_store,saeki-masaki/glance_store,hmakkapati/glance_store,openstack/glance_store,cpallares/glance_store,redhat-openstack/glance_store