Merge 9c9ceecc47 into master

* commit 9c9ceecc47e:
  Fix standalone build, reference plugin API 2.13.9
  Revert "Add support for Bazel in Gerrit tree build"

This merge uses "-s ours" strategy, which keeps master unchanged.  We
don't want these two changes in master.  The purpose of this merge is to
create a merge-base for the follow-up merges.

Change-Id: I408f0d93cb4085411a96e74aafbd9c6c5eae8805