The most important bits are updating shade references to remove
the openstack-infra. The other git urls will work through the
redirect, but cleaning them up is just nicer.

This removes two comments that reference files that no longer
exist due to config generation.

Also, fix some random use of github for cloning openstack repos,
since the github mirror is best-effort only.

Change-Id: I55a1d9db940cf5fa2c35421db7add015ae334563
Needed-By: https://review.opendev.org/654056