With this change, all Horizon unit tests pass on Python 3.4.
Changes:
* vpn/tests.py, firewalls/tests.py: Replace reverse_lazy() with
reverse() to get a regular Python string. The lazy object caused
failures on Python 3.
* routers/tests.py: Decode HTTP body to get Unicode on Python 3. It
works also on Python 2.
* neutron.py: replace a/b with a//b to get an integer on Python 3.
* network_tests.py: remove useless copy.deepcopy() which caused a
recursion error on Python 3.
* metadata_defs/tests.py: expect a different JSON error message on
Python 3.
* tox.ini: remove openstack_dashboard whitelist, all unit tests now
pass on Python 3 ;-)
Partial-Implements: blueprint porting-python3
Change-Id: I7b4f036fc86b66c92cccafe6938a906045f03186