don't close std* fd if opentty fails

We didn't do it before, and it makes testcases fail.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

src/lxc/lxc_usernsexec.c

@@ -83,15 +83,13 @@ static void opentty(const char * tty, int which) {
 	fd = open(tty, O_RDWR | O_NONBLOCK);
 	if (fd == -1) {
 		printf("WARN: could not reopen tty: %s\n", strerror(errno));
-		close(which);
 		return;
 	}
 
 	flags = fcntl(fd, F_GETFL);
 	flags &= ~O_NONBLOCK;
 	if (fcntl(fd, F_SETFL, flags) < 0) {
 		printf("WARN: could not set fd flags: %s\n", strerror(errno));
-		close(which);
 		return;
 	}