[IMP] travis_install_nightly: prioritize main repo's requirements (#357)
[IMP] travis_install_nightly: prioritize main repo's requirements (#357)

Python requirements defined in te main repo should have priority over
anything else, including other repos and even packages with pinned
versions here (e.g. cryptography).
Vauxoo/maintainer-quality-tools,Vauxoo/maintainer-quality-tools,Vauxoo/maintainer-quality-tools