Fixes KeyError bug with network api associate

Fixes bug in network api associate function where it would always
raise a KeyError when associating or disassociating a project.

Fixes bug 1171284

Conflicts:

	nova/tests/network/test_api.py

Change-Id: Iae0e57e0a961b8a3377b38dad72094188755a3e8
(cherry picked from commit 6cfc02531f92c2e98eb947bc7a46d6bed0158d82)
Merge "Fixes KeyError bug with network api associate" into stable/grizzly
Merge remote-tracking branch 'upstream/stable/grizzly' into stable/grizzly