Disable the Datadog agent on jenkins master for tools core

We saw failures filling up the system log, and it's not worth troubleshooting
at the current time as we do not use that data.

playbooks/edx-east/jenkins_build.yml

@@ -11,7 +11,7 @@
   become: True
   gather_facts: True
   vars:
-    COMMON_ENABLE_DATADOG: True
+    COMMON_ENABLE_DATADOG: False
     COMMON_ENABLE_SPLUNKFORWARDER: True
     COMMON_ENABLE_NEWRELIC: True
     COMMON_SECURITY_UPDATES: yes