Double the time spent waiting for a UseCircuitCode packet in LLUDPServer.HandleCompleteMovementIntoRegion()

This is to deal with one aspect of http://opensimulator.org/mantis/view.php?id=6755
With the V2 teleport arrangements, viewers appear to send the single UseCircuitCode and CompleteAgentMovement packets immediately after each other
Possibly, on occasion a poor network might drop the initial UseCircuitCode packet and by the time it retries, the CompleteAgementMovement has timed out and the teleport fails.
There's no apparant harm in doubling the wait time (most times only one wait will be performed) so trying this.