Convert the charm to Python 3

Change-Id: I8c8df27be189098be363d0ea125f86e59fdbb020

.zuul.yaml

@@ -1,4 +1,3 @@
 - project:
     templates:
-      - python-charm-jobs
-      - openstack-python35-jobs-nonvoting
+      - python35-charm-jobs

actions/actions.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #
@@ -17,7 +17,19 @@
 import os
 import sys
 
-sys.path.append('hooks/')
+
+_path = os.path.dirname(os.path.realpath(__file__))
+_hooks = os.path.abspath(os.path.join(_path, '../hooks'))
+_root = os.path.abspath(os.path.join(_path, '..'))
+
+
+def _add_path(path):
+    if path not in sys.path:
+        sys.path.insert(1, path)
+
+_add_path(_hooks)
+_add_path(_root)
+
 
 from charmhelpers.core.hookenv import action_fail
 from ceilometer_utils import (

charm-helpers-hooks.yaml

@@ -1,5 +1,5 @@
 repo: https://github.com/juju/charm-helpers
-destination: hooks/charmhelpers
+destination: charmhelpers
 include:
     - core
     - osplatform