Use option name --test-commandline in tor-fw-helper.

Use option name --test-commandline in tor-fw-helper.

It was previously --Test in the help output and --test-commandline in
the getopt call. The man page already had --test.

  (Originally by David, who resolved the tie in favor of "--test"; I
   chose --test-commandline" instead so that nothing that depended
   on it could break. -Nick)