Merge branch 'stable-3.3'

Update API version to 3.4.0.

* stable-3.3:
  Batch plugin: refactor BatchSubmitter
  Fix errors against latest Gerrit core
  Update WORKSPACE to use released api version
  Upgrade bazlets to latest stable-3.2 to build with 3.2.6 API
  Upgrade bazlets to latest stable-3.1 to build with 3.1.11 API
  Upgrade bazlets to latest stable-3.2 to build with 3.2.5.1 API
  Upgrade bazlets to latest stable-3.1 to build with 3.1.10 API

Change-Id: Ic1f43562a45f6e4b355bae046d6925c6a465fa5a