libvirt-python: three patches on Makefile, tox.ini, and domstart.py

[Ariel Otilibili]

Hello,

I have been using libvirt for some years, and this is my first ever 
contribution; your feedback is more than welcome.

This is a set of patches about changes done in Makefile, tox.ini, and 
domstart.py.

Regards,
Ariel