Updated openstack/openstack
Project: openstack/nova  3cda85435f34a14c1cb3e8cfa9de05445ba36207

xenapi: move StorageError into global exception.py

We have our own exception for StorageErrors, and this is causing some
interesting dependency issues, so seems best to move this exception into
the more usual place.

Change-Id: I4f1f33e95f1050874ef828af9b35b0edbf8f0176