Revert a workaround for Windows 7 RC

Windows 7 SP1 (32 bit) + cygwin 1.7.25 does not need the workaround.
Windows 8.1 (64 bit) + cygwin 1.7.25 (64 bit)
does not need the workaround, too.
Fix the problem that is fakecygpty without any options

This commit adds an error message "Unable to get arg[1]."
Fix return status

From ２ちゃんねる NTEmacs スレッド 3
736: 2013-12-08T18:23:58.30+09:00
737: 2013-12-08T19:31:05.38+09:00
http://anago.2ch.net/test/read.cgi/software/1325573999/