An attempt to prevent the ugly exceptions from being raised on quit.

src/Owner.py

@@ -325,7 +325,12 @@ class Owner(privmsgs.CapabilityCheckingPrivmsg):
         world.dying = True
         for driver in drivers._drivers.itervalues():
             driver.die()
+        killed = sets.Set()
         for irc in world.ircs[:]:
+            # The following is so callbacks don't get killed multiple times
+            # when the Relay plugin is loaded:
+            if id(irc.callbacks) not in killed:
+                killed.add(id(irc.callbacks))
                 irc.die()
         raise SystemExit, 'Quitting because I was told by %s' % msg.prefix