Forced isolation for the nova quota test

Several test cases like quota related tests should not be done without
creating a new tenant in all cases.

This change enforces the isolated code path for the nova quota tests.
These tests requires admin rights anyway, so probably no one want to
try to run them without admin permissions.

Change-Id: Ib7550bc68f493ce9c6acbd57fc2d901e14ec2fef
2 files changed