selftests: mptcp: always close input's FD if opened

BugLink: https://bugs.launchpad.net/bugs/2083488

commit 7c70bcc2a84cf925f655ea1ac4b8088062b144a3 upstream.

In main_loop_s function, when the open(cfg_input, O_RDONLY) function is
run, the last fd is not closed if the "--cfg_repeat > 0" branch is not
taken.

Fixes: 05be5e273c ("selftests: mptcp: add disconnect tests")
Cc: stable@vger.kernel.org
Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

tools/testing/selftests/net/mptcp/mptcp_connect.c

@@ -1115,11 +1115,11 @@ again:
 		return 1;
 	}
 
-	if (--cfg_repeat > 0) {
-		if (cfg_input)
-			close(fd);
+	if (cfg_input)
+		close(fd);
+
+	if (--cfg_repeat > 0)
 		goto again;
-	}
 
 	return 0;
 }