location overrides not working as expected

[Tom Haddon]

In the PQM config, there's a [location overrides] section. However it doesn't seem to work as expected. This was during testing a migration from sftp -> bzr+ssh. Here's what was done:

- Changed entries in build_config file for each branch to use bzr+ssh instead of sftp
- Added the following location overrides (the first one was already there):

[location overrides]
/home/pqm/archives/rocketfuel=sftp://devpad.canonical.com/code/rocketfuel
/home/pqm/archives/rocketfuel=bzr+ssh://devpad.canonical.com/code/rocketfuel
bzr+ssh://devpad.canonical.com/=sftp://devpad.canonical.com/

- Changed the published_at locations to be bzr+ssh instead of sftp

However, the PQM web interface (even after a restart) was reporting "Request for non-PQM managed branch." for all branches in the queue.

Reverted, and everything was back to normal.