fix crash after introduction of immediate mode

fix crash after introduction of immediate mode

this fixes the following backtrace:

Exception happened during processing of request from ('127.0.0.1', 41192)
Traceback (most recent call last):
  File /usr/lib/python2.7/SocketServer.py, line 295, in _handle_request_noblock
    self.process_request(request, client_address)
  File /usr/lib/python2.7/SocketServer.py, line 321, in process_request
    self.finish_request(request, client_address)
  File /usr/lib/python2.7/SocketServer.py, line 334, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File /usr/lib/python2.7/SocketServer.py, line 649, in __init__
    self.handle()
  File ./irkerd, line 820, in handle
    irker.handle(line.strip())
  File ./irkerd, line 786, in handle
    self.servers[target.server()].dispatch(target.channel, message, target.key, quit_after=quit_after)
  File ./irkerd, line 641, in dispatch
    eligibles[0].enqueue(channel, message, key)
TypeError: enqueue() takes exactly 5 arguments (4 given)

when running: ./irk irker-test test