Merge branch 'tcp-revert-a-F-RTO-extension-due-to-broken-middle-boxes'

Yuchung Cheng says:

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tcp: revert a F-RTO extension due to broken middle-boxes

This patch series reverts a (non-standard) TCP F-RTO extension that aimed
to detect more spurious timeouts. Unfortunately it could result in poor
performance due to broken middle-boxes that modify TCP packets. E.g.
https://www.spinics.net/lists/netdev/msg484154.html
We believe the best and simplest solution is to just revert the change.
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Signed-off-by: David S. Miller <[email protected]>