Tests dir no longer need copy of charmhelpers

Charmhelpers is now installed via pip for unit tests so stop
'Make sync' from pulling it down.

Change-Id: I65cb2ffc3ac78215c1a3daba067d28241c090c57

Makefile

@@ -23,7 +23,6 @@ bin/git_sync.py:
 
 ch-sync: bin/charm_helpers_sync.py
 	$(PYTHON) bin/charm_helpers_sync.py -c charm-helpers-hooks.yaml
-	$(PYTHON) bin/charm_helpers_sync.py -c charm-helpers-tests.yaml
 
 ceph-sync:  bin/git_sync.py
 	$(PYTHON) bin/git_sync.py -d lib -s https://github.com/openstack/charms.ceph.git

charm-helpers-tests.yaml

@@ -1,7 +0,0 @@
-repo: https://github.com/juju/charm-helpers
-destination: tests/charmhelpers
-include:
-    - contrib.amulet
-    - contrib.openstack.amulet
-    - core
-    - osplatform