Update amulet test definitions for Newton

- Remove Precise-Icehouse Amulet test definitions if they exist.

- Add Xenial-Newton Amulet test definitions.

- Add Yakkety-Newton Amulet test definitions.

- Use the percona-cluster charm in tests instead of the mysql charm.

Change-Id: Icb3adfbe08c9db339499f69523f7b223dda94c0c

hooks/charmhelpers/contrib/openstack/utils.py

@@ -229,6 +229,7 @@ GIT_DEFAULT_REPOS = {
 GIT_DEFAULT_BRANCHES = {
     'liberty': 'stable/liberty',
     'mitaka': 'stable/mitaka',
+    'newton': 'stable/newton',
     'master': 'master',
 }
 
@@ -735,12 +736,12 @@ def git_os_codename_install_source(projects_yaml):
 
         if projects in GIT_DEFAULT_BRANCHES.keys():
             if projects == 'master':
-                return 'newton'
+                return 'ocata'
             return projects
 
         if 'release' in projects:
             if projects['release'] == 'master':
-                return 'newton'
+                return 'ocata'
             return projects['release']
 
     return None