Add a assertRaisesAny helper method

Instead of having special logic that checks if a
group of expected exceptions are raised and fails
if they are not just use the testtools framework
to provide a similar function that integrates
more natively with testtools.

Change-Id: I063e9832c825cf2b528c7f8899714a8a440f17a5
Merge "Add a assertRaisesAny helper method"