Use unittest 0.6.0

Unittest 0.7+ is going to behave like unittest from Python 3.4,
which is that expectedFailure's must fail, which is different
from Python 2.7 and 3.3 unittest.

https://code.google.com/p/unittest-ext/issues/detail?id=85

Bug: 72801
Change-Id: I7480b6021c76aa4383140e229b6c877a6833a7ef