message: fix disconnect check in mininode
diff: @@ -65,6 +65,7 @@ class NodeConnCB(object):
  # tests; it causes message delivery to sleep for the specified time
  # before acquiring the global lock and delivering the next message.
  self.deliver_sleep_time = None
  + self.disconnected = False
  def set_deliver_sleep_time(self, value):
  with mininode_lock:
  @@ -141,7 +142,9 @@ class NodeConnCB(object):
  def on_reject(self, conn, message): pass
  - def on_close(self, conn): pass
  + def on_close(self, conn):
  + self.disconnected=True
  + pass
  def on_mempool(self, conn): pass
  