Don't sys_kill SELF if a PM exit fails; just generate a fault to get

us killed through the kernel with PM finding out.

This makes it unnecessary for servers and drivers to be able to do
sys_kill generally, so KILL can go out of /etc/drivers.conf.

lib/syslib/panic.c

@@ -30,9 +30,6 @@ int num;			/* number to go with format string */
       }
   }
 
-  /* Try to signal ourself */
-  sys_kill(SELF, SIGKILL);
-
   /* If exiting nicely through PM fails for some reason, try to
    * commit suicide. E.g., message to PM might fail due to deadlock.
    */