Reduce severity of "Killed by signal %d"

This produces irritating messages when using ProxyCommand or other programs
that use ssh under the covers (e.g. Subversion).  These messages are more
normally printed by the calling program, such as the shell.

According to the upstream bug, the right way to avoid this is to use the -q
option, so we may drop this patch after further investigation into whether
any software in Debian is still relying on it.

Author: Colin Watson <cjwatson@debian.org>
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1118
Bug-Debian: http://bugs.debian.org/313371
Last-Update: 2013-09-14

Patch-Name: quieter-signals.patch

clientloop.c

@@ -1717,8 +1717,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
 		exit_status = 0;
 	}
 
-	if (received_signal)
-		fatal("Killed by signal %d.", (int) received_signal);
+	if (received_signal) {
+		debug("Killed by signal %d.", (int) received_signal);
+		cleanup_exit((int) received_signal + 128);
+	}
 
 	/*
 	 * In interactive mode (with pseudo tty) display a message indicating