Fixes spring-projects/spring-integration-samples#198 The `SocketUtils.findAvailableServerSocket()` isn't reliable for port selection and its `socket.close()` may cause a port selection by some other process. Use OS-selected port for SshdServer in SFTP sample Revert unexpected refactoring after renaming properties Upgrade to SSHD-1.4, FTP Server 1.1, fix tests and Boot 2.0 compatibility