[svn r37787] more precision at shutdown: first remove

from the sendqueue, then trigger the queue
to shutdown. (This is an attempt to get
rid of the still appearing "exception in thread"
messages)

--HG--
branch : trunk

py/execnet/gateway.py

@@ -275,11 +275,12 @@ class Gateway(object):
 ##            self._exitlock.release()
 
     def exit(self):
-        self._outgoing.put(None)
         try:
             del _active_sendqueues[self._outgoing]
         except KeyError:
             pass
+        else:
+            self._outgoing.put(None)
 
     def join(self, joinexec=True):
         current = threading.currentThread()