Patch to log tunnel information

[jblaine at kickflop.net]

First, all credit to Vladimir Parkhaev as this is his code.  He may have
submitted this before for all I know, but I for one definitely would like
to see this end up in the codebase, so I'm submitting it.

*** openssh-5.1p1/serverloop.c  Fri Jul  4 09:10:49 2008
--- openssh-5.1p1-RCFHACKS/serverloop.c Thu Jan 29 08:56:11 2009
***************
*** 957,962 ****
--- 957,968 ----
        c = channel_connect_to(target, target_port,
            "direct-tcpip", "direct-tcpip");

+     if (c == NULL){
+         verbose("Tunnel denied: user '%s' from %s to %s:%d",
the_authctxt->user, get_remote_ipaddr(), target, target_port);
+     } else {
+         verbose("Tunnel opened: user '%s' from %s to %s:%d",
the_authctxt->user, get_remote_ipaddr(), target, target_port);
+     }
+
        xfree(originator);
        xfree(target);