Trigger remote update HEAD

Listen to update HEAD events and trigger a remote update HEAD over REST
API.

Since replicas do not have REST API, this is currently working just for
primary instances. The implementation for replicas will be provided as a
follow up change.

Bug: Issue 15258
Change-Id: Ic19d4ac15387830c98a87438cfd3bcf881a90845
9 files changed
tree: 921f1589930e67aaf9c4a01437725a51dc57886b
  1. src/
  2. BUILD
  3. Jenkinsfile
  4. LICENSE