Fix bug #137823 by raising UnavailableFeature *after* the fake ftp server setup is completed.
* bzrlib/transport/ftp.py: (get_test_permutations.UnavailableFTPServer): Raising an exception during setup is not correctly handled by the test framework. Better raise it on get_url() and get_bogus_url() which are always called first when using a server.
* bzrlib/builtins.py: (cmd_selftest.run): 'info()' is about to be deprecated, use note() instead.