Merge branch 'stable-3.4'

* stable-3.4:
  Fix 'illegal format conversion' compilation error
  Use stream events to fetch refs and create repositories
  Use gerrit.instanceId instead of replication.instanceLabel
  Extract FetchApiClient interface
  Add user/password authentication for CGit client

Change-Id: I4d9daab055d364a9773325ac6e713766424ed749