Merge "Simulate normal ansible behaviour with shared role"

ansible/roles/common/defaults/main.yml

 ---
+# Due to the way we do our inventory, ansible does not pick up on the fact that
+# this role has already run. We can track what has run with host facts.
+common_run: False
+
 ####################
 # Docker
 ####################

ansible/roles/common/tasks/main.yml

 ---
 - include: "{{ action }}.yml"
+  when: not common_run
+
+- name: Registering common role has run
+  set_fact:
+    common_run: True
+  when: not common_run