Fix typo in identity:list_role_assignments policy

Change-Id: I3c154b8e16f6e45a13a5045062e68b4d9f475211
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>
Cleanup backend loading

Backend creation was happening at import time. This changes the
code so that backend creation time is controlled by calling a
function.

This also allows sharing the backend creation code between the
server and the tests.

Change-Id: Ib817aa341de510a46faa8ed0bc24ef9268fa944b
Merge "Cleanup backend loading"
Merge "Fix typo in identity:list_role_assignments policy"