pgsql: Allow transactions that don't write WAL to commit asynchronously

Allow transactions that don't write WAL to commit asynchronously.

This case can arise if a transaction has written data, but only to
temporary tables.  Loss of the commit record in case of a crash won't
matter, because the temporary tables will be lost anyway.

Reviewed by Heikki Linnakangas and Simon Riggs.

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=f6a0863e3cb72763490ceca2c558d5ef2dddd5f2

Modified Files
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src/backend/access/transam/xact.c |   33 +++++++++++++++++++++++----------
1 files changed, 23 insertions(+), 10 deletions(-)