All tests in nova/tests/unit/objects/test*.py now run with
python3.4 tox target.
* Fix imports in limits.py and urlmap.py
* Add a list() as keys()/values() return iterator in
availability_zones.py, flavors.py and instance_numa_topology.py
* contextlib.nested is not present in python3, so whip up an
alternative using ExitStack(). Directly using ExitStack() wont
work for us.
* Add a few assertJsonEqual in the test cases
* Ensure fingerprinting generates the same exact value in both
python27 and python34
Blueprint nova-python3
Change-Id: I848c48475189c4b4ad8151e14509020ae7d110a4