Merge branch 'stable-3.2' into master

* stable-3.2:
  Elasticsearch: Remove support for EOL 6.7 version
  Update the recommended buildifier version to 3.5.0
  Remove unused Documentation/config-login-register.txt

Change-Id: I4c707f5c14dd778595206ef0a8cb80d0c8805ffc
tree: 61b55419c5fa7c3b60f386e063714a64f71f5ce7
  1. java/
  2. javatests/