Tests: Fix CTestTestFailedSubmit-ftp with OS X system libcurl

On OS X 10.9 the system libcurl has a different error message when
failing to connect:

  Failed connect to :21; Connection refused

Match this message to pass the test.
Fix messages.
Merge topic 'install-prefix-in-interface' into next

73bdbe71 Fix messages.
Merge topic 'fix-CTestTestFailedSubmit-ftp-for-osx-system-curl' into next

63d864a0 Tests: Fix CTestTestFailedSubmit-ftp with OS X system libcurl