pgsql: Cope with heap_fetch failure while locking an update chain

Cope with heap_fetch failure while locking an update chain

The reason for the fetch failure is that the tuple was removed because
it was dead; so the failure is innocuous and can be ignored.  Moreover,
there's no need for further work and we can return success to the caller
immediately.  EvalPlanQualFetch is doing something very similar to this
already.

Report and test case from Andres Freund in
20131124000203.GA4403@alap2.anarazel.de

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/e518fa7adfc28e0d0a99fe4e5711386d9a5c6532

Modified Files
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src/backend/access/heap/heapam.c |   11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)