Unable to authenticate user without metadata

I'm not sure how others are having this work, but with the following information, I'm getting this traceback: http://paste.openstack.org/show/7892/

...when authenticating.

root@auth:~# keystone service-list
+----------------------------------+---------+---------+-------------+
| id | name | type | description |
+----------------------------------+---------+---------+-------------+
| 11effbca50f048f4bfb4f551daaea61a | compute | compute | None |
| e778c89aa29b405ca8d09a3263f70e2d | image | image | None |
+----------------------------------+---------+---------+-------------+

root@auth:~# keystone endpoint-list
+----------------------------------+-----------+--------------------------------+--------------------------------+--------------------------------+
| id | region | publicurl | internalurl | publicurl |
+----------------------------------+-----------+--------------------------------+--------------------------------+--------------------------------+
| b672526d813d4954b4d79c9a02b2e010 | RegionOne | http://api1:8774/v2.0/ | http://api1:8774/v2.0/ | http://api1:8774/v2.0/ |
| e766756c860a412d9060b8406f466ba9 | RegionOne | http://glance-api1:9292/v1/ | http://glance-api1:9292/v1/ | http://glance-api1:9292/v1/ |
+----------------------------------+-----------+--------------------------------+--------------------------------+--------------------------------+

root@auth:~# keystone user-list
+----------------------------------+---------+-------+-------+
| id | enabled | email | name |
+----------------------------------+---------+-------+-------+
| b8b494c26cee48619592e998533dda1a | True | None | admin |
+----------------------------------+---------+-------+-------+

root@auth:~# keystone tenant-list
+----------------------------------+-------+---------+
| id | name | enabled |
+----------------------------------+-------+---------+
| 788ca2f80f4b4fa7acb9de943196f366 | admin | True |
+----------------------------------+-------+---------+

The fix seems to be a very simple one-liner which updates a "get_metadata" call to return an empty dictionary instead of None.