Reuse Gerrit code for head update

To avoid code duplication and to make sure that head update is done
correctly replace pull-replication custom code with the code from Gerrit
core.

Bug: Issue 15396
Change-Id: Ic49b731a8e5394ead3a4d36134db7a38f068718d
1 file changed
tree: c2ab4763c01da72c5ee1d0c28487b0e36b39597a
  1. src/
  2. BUILD
  3. Jenkinsfile
  4. LICENSE