Merge branch 'stable-5.7' into stable-5.8

Merge branch 'stable-5.7' into stable-5.8

* stable-5.7:
  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: Ibe46e8479b57a54591ad7bd3cc29bf4a5274e43d