Merge branch 'stable-5.11' into stable-5.12

Merge branch 'stable-5.11' into stable-5.12

* stable-5.11:
  Add missing @since tags
  Add missing @since tag
  Add missing @since tags
  Remove unused import in ApacheSshTest
  Update maven plugins
  Ignore missing javadoc in test bundles
  storage: file: De-duplicate File.exists()+File.isFile()
  RefDirectory.scanRef: Re-use file existence check done in snapshot creation
  FileSnapshot: Lazy load file store attributes cache
  Update eclipse-jarsigner-plugin to 1.3.2
  Fix p2 repository URLs

Change-Id: I72f39fbe82dd578d71aa2e3ceccebb39a25c4e00