Fix a long-standing bug that resulted in a dropped session sometimes

when an X11-forwarded client was closed.  For some reason, sshd didn't
disable the SIGPIPE exit handler and died a horrible death (well, okay,
a silent death really).  Set SIGPIPE's handler to SIG_IGN.

crypto/openssh/sshd.c

@@ -1061,6 +1061,7 @@ main(int ac, char **av)
 	signal(SIGTERM, SIG_DFL);
 	signal(SIGQUIT, SIG_DFL);
 	signal(SIGCHLD, SIG_DFL);
+	signal(SIGPIPE, SIG_IGN);
 
 	/*
 	 * Set socket options for the connection.  We want the socket to