
When datapath reconnects/disconnects, waiting requests on old
datapath should be canceled. Otherwise, threads that sent
requests may fall into deadlock because replies possibly never
come.
This patch is backport of the Ryu patch [1].
Related-Bug: #1944201
[1] 6f906e72c9
Change-Id: I0bde9df2cd651b88e60631b53d69ad50f8d86d02