Fix a leak in the recent fixes for file descriptors > SHRT_MAX. In the

case of a file descriptor we can't handle, clear the FILE structure's flags
so it can be reused.

MFC after:	1 week
Reported by:	otto @ OpenBSD

lib/libc/stdio/fopen.c

@@ -73,6 +73,7 @@ fopen(file, mode)
 	 * open.
 	 */
 	if (f > SHRT_MAX) {
+		fp->_flags = 0;			/* release */
 		_close(f);
 		errno = EMFILE;
 		return (NULL);