pgsql: Further cleanup of ReorderBufferCommit().

Further cleanup of ReorderBufferCommit().

On closer inspection, we can remove the "volatile" qualifier on
"using_subtxn" so long as we initialize that before the PG_TRY block,
which there's no particularly good reason not to do.
Also, push the "change" variable inside the PG_TRY so as to remove
all question of whether it needs "volatile", and remove useless
early initializations of "snapshow_now" and "using_subtxn".

Branch
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REL9_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/f86a8955e8aae4da854e65b87b588e37ecb45918

Modified Files
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src/backend/replication/logical/reorderbuffer.c | 34 +++++++++++------------
1 file changed, 17 insertions(+), 17 deletions(-)