Includes updates to charmhelpers/charms.openstack for cert_utils
and unit-get for the install hook error on Juju 2.9
* charm-helpers sync for classic charms
* rebuild for reactive charms
* ensure tox.ini is from release-tools
* ensure requirements.txt files are from release-tools
* On reactive charms:
- ensure master branch for charms.openstack
- ensure master branch for charm-helpers
* Fixes to unit tests due to removal of unit_get from context.
Change-Id: I83f12c9e010468be34637056e645f2bfc732f2df