Migrate from nose to testr.

Run tests with testr for parallel execution.

Part of blueprint grizzly-testtools.

Change-Id: I560592186f2f440049a451a32e58067262ab62d0
Remove incorrect 'raise'.

Fixes bug 1096102.

Change-Id: Ibcdccd949566f47bb516c7562149d6b0100fce18
Merge "Remove incorrect 'raise'."