Add py34 to test environment to tox.ini
Add py34 to test environment to tox.ini

Manila code base was updated to work on top of python3.4
So, add its test environment to tox.ini

Change-Id: I1403b6b758de52110a53e571c81863c98e909b99

vponomaryov/manila,scality/manila,scality/manila,bswartz/manila,openstack/manila,jcsp/manila,bswartz/manila,openstack/manila,vponomaryov/manila,redhat-openstack/manila,jcsp/manila,redhat-openstack/manila,NetApp/manila,NetApp/manila