Adjust expected error message in FailedSubmit-ftp

Error message from cygwin's curl (using `../bootstrap --system-libs` or `cmake .. -DCMAKE_USE_SYSTEM_LIBRARIES=ON`, then `ctest -V -R ftp` in cygwin) in CTestTestFailedSubmit-ftp was:
`Failed to connect to  port 21: Connection timed out`, causing this test to fail. Slight extension of this expected error message regex catches this version.