Major changes:
* decoupling the hooks/manager.py file from the charm. It is now a
script that is called from hooks/keystone_utils.py as it has to use
the same Python version/libraries as the installed keystone payload
software. keystone_utils.py and manager.py communicate via a Unix
Domain Socket using json, encoded to base64.
* As Python3 requires absolute imports, the charmhelpers symlink has
been removed from hooks, and the hooks and charmhelpers symlinks have
been removed from the actions directory. Instead, the path is
adjusted so that the modules can be found.
Change-Id: I18996e15d2d08b1dacf0533132eae880cbb9aa32
59561fdda0