Idle units pushed each other in front of a house for several minutes

[AndreiCherniaev]

Map and save
Digging Rush_.zip
Digging Rush_deadlock.zip

P.S. I still think algo should be improved, see details in #648

r17915

[Kromster80]

I have watched the replay, the traffic jam was periodically occurring there since the school was built. That is why it is a bad idea to place the School into a dead-end like that.

Usually it cleared up in 3-15 exchanges, but the Woodcutters were stuck in a loop for several minutes (24:30 - 32:45).