pymod2pkg: Add testing for Python 3.x
pymod2pkg: Add testing for Python 3.x

This project is supposed to be Python 2.x/3.x compatible, so
we should test for it.

Change-Id: I11c9a2f0435c66631ca83f60ba51536cb16b8358

openstack-infra/project-config,dongwenjuan/project-config,dongwenjuan/project-config,Tesora/tesora-project-config,Tesora/tesora-project-config,openstack-infra/project-config