Revert "Merge branch 'wc-gitaly-keepalive-limit' into 'master'"

Merged Stan Hu requested to merge revert-b574ddd8 into master

What does this MR do and why?

This reverts !73302 (merged). This setting causes long-running RPCs to shut down and causes the client to receive GOAWAY messages from the server. As explained in, configuring Gitaly keepalive settings is dangerous: if the client sends too many, then the server will abruptly shut down the connection, causing RPCs to fail.

At the moment, it doesn't appear grpc-go has a way to configure or even disable this shutdown mechanism (I submitted For now, we should revert this change because it does more harm than good.

Go 1.13 should have enabled 15-second TCP keepalives by default; I'm not sure yet why this isn't working, or whether gRPC is fiddling with this as well.

Relates to #350580 (closed)

MR acceptance checklist

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Edited by Stan Hu