Add canonical hostname to source object

This is the start of the implementation of:
http://lists.openstack.org/pipermail/openstack-infra/2017-March/005208.html

It lets us associate a canonical hostname with every connection
that we will later use to uniquely identify source code repos.

Story: 2000953
Change-Id: I7f2e64944d46f304e63a54078e682fd5e1682f27
6 files changed