pgsql: Don't pay heed to wal_sender_timeout while creating a decoding s

Don't pay heed to wal_sender_timeout while creating a decoding slot.

Sometimes CREATE_REPLICATION_SLOT ... LOGICAL ... needs to wait for
further WAL using WalSndWaitForWal(). That used to always respect
wal_sender_timeout and kill the session when waiting long enough
because no feedback/ping messages can be sent while the slot is still
being created.
Introduce the notion that last_reply_timestamp = 0 means that the
walsender currently doesn't need timeout processing to avoid that
problem. Use that notion for CREATE_REPLICATION_SLOT ... LOGICAL.

Bugreport and initial patch by Steve Singer, revised by me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/21d48d66c8be053ef5ce0474bb30f8a91b7c3dd6

Modified Files
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src/backend/replication/walsender.c |   31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)