py3: Enable more tests to Python 3.4
py3: Enable more tests to Python 3.4

tox.ini: add more tests which pass on Python 3.4.

Remove also the duplicated "deps" option: the value is [testenv] is
the same.

Partially-Implements: blueprint barbican-py3
Change-Id: I7199bed61c0f57df183f518f3df1e48a1b4b0bd9

openstack/barbican,openstack/barbican