Merge branch 'stable-2.14' into stable-2.15

* stable-2.14:
  Fix typo in sample gerrit.config
  Align handling of configuration error with other plugins
  Introduce sslVerify configuration parameter
  Remove redundant SSL Socket Factory set
  Postpone retrieval of HttpSession
  Add possibility to override global configuration per remote
  Fix threads leak when PostTask is executed
  Add headers to EventProcessor
  Introduce events processor

Change-Id: Ida9d1e82d4b749c28a1d99264652a832264c9598