Including dependency for Zimbra role

.travis.yml

@@ -21,6 +21,8 @@ install:
   # Create ansible.cfg with correct roles_path
   - printf '[defaults]\nroles_path=../' >ansible.cfg
 
+  # Install ansible-commons
+  - ansible-galaxy install lucascbeyeler.ansible-commons
 script:
   # Basic role syntax check
   - ansible-playbook tests/test.yml -i tests/inventory --syntax-check