Merge branch 'stable-2.15' into stable-2.16

* stable-2.15:
  Revert "Remove replication event from pending when runway is allowed"
  ReplicationFileBasedConfig: Fix setting default sshConnectionTimeout
  SshHelper: Add class javadoc
  Make more classes and fields public to ease extensibility
  Allow to configure timeout for SSH connection and commands
  StartCommand:  Fix synchronization on non-final field
  Destination: Suppress FutureReturnValueIgnored warning

Change-Id: I0cbbf0db0bb8d6b44e7f86ec7ad3e0f2067f3a6d