SSH data race

[ivcosla]

Sometimes when executing ssh integration environment, and running ssh test a data race appears on the ssh server node. Attached are the logs for every node, the data race appears in A log, line 126.

nodeA.log nodeB.log nodeC.log

[evanlinjin]

Looking at the logs, I see: panic: send on closed channel -> A quick hack is to use sync.Mutex to ensure close/write actions do not overlap. Of cause, if there is a more elegant, yet obvious, solution, do that instead.