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
* Remove mock for unit_get() as removed from the context module
Change-Id: I1c68e1ad512d947b62c8cef6d1cc585270f64972
055446e5c5