Merge branch 'stable-2.13'

* stable-2.13:
  Add hostname label to Gerrit Metrics in ElasticSearch
  Update ElasticSearch library and its dependencies

Change-Id: Idd7040ca41cb77337c00bad1d61b284f37d8c3a4
tree: 2d73c6dbc4f6b025b03249f7318c4cf8bae3433b
  1. BUILD
  2. external_plugin_deps.bzl
  3. src/