Merge branch 'stable-3.5' into stable-3.6

* stable-3.5:
  Fix ApplyObjectActionIT flakiness due to the wrong ref used
  Index change asynchronously upon refs replicated event
  Address follow-up comments to Change 396868
  Introduce wait for replication events to reduce flaky tests
  Fail apply-object on change /meta when missing patch-set

Release-Notes: skip
Change-Id: Ic1d47063bdb2f13eb8ed18e7091ae9c967bef9ab