Adds support for patching OpenStack services

This commit adds support for patching OpenStack services.  This
will help retire the openstack-ha module which will no longer be
needed with the completion of the openstack-installer project.
This will also allow us to manage patches that COI/COE will
support.

The first patch being implemented is for impl_kombu.py, which
is needed to address the following HA-related bug:

https://bugs.launchpad.net/oslo/+bug/856764