Updated openstack/openstack
Project: openstack/glance  e7413091c3e0031d74e2c5c63dac708c02ed63c8
null
Clean up DatabaseMigrationError

Exception DatabaseMigrationError from glance/common/exception.py
is unused, so we get rid of it.

Change-Id: I36f70dcc7d5b282d3c9d9e82a0c3f673d008e71e