Make datadog optional for jenkins_master.

playbooks/edx-east/jenkins_master.yml

@@ -8,6 +8,8 @@
   gather_facts: True
   vars:
     COMMON_DATA_DIR: "/mnt"
+    COMMON_ENABLE_DATADOG: True
   roles:
     - common
+    - datadog
     - jenkins_master

playbooks/roles/jenkins_master/meta/main.yml

 ---
 dependencies:
   - common
-  - role: datadog
-    COMMON_ENABLE_DATADOG: True

playbooks/roles/jenkins_master/tasks/main.yml

@@ -128,3 +128,4 @@
   notify: start nginx
 
 - include: datadog.yml tags=datadog
+  when: COMMON_ENABLE_DATADOG