Drop py34 target in tox.ini and setup.cfg
Drop py34 target in tox.ini and setup.cfg

We support py35 now. We do not have python 3.4 in setup.cfg which
declares the explicit supported versions. so it is no need to keep
 the supoort for py34.

Change-Id: I8a2176e020714a1577573f1453ce1892706b36e4

openstack/horizon,yeming233/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,yeming233/horizon,yeming233/horizon,NeCTAR-RC/horizon,noironetworks/horizon,ChameleonCloud/horizon,openstack/horizon,BiznetGIO/horizon,openstack/horizon,ChameleonCloud/horizon,noironetworks/horizon,ChameleonCloud/horizon,openstack/horizon,BiznetGIO/horizon,BiznetGIO/horizon,noironetworks/horizon,yeming233/horizon,NeCTAR-RC/horizon,BiznetGIO/horizon,NeCTAR-RC/horizon,noironetworks/horizon