[COMMITTERS] pgsql: Set ecxt_scantuple correctly for tuple routing.

Set ecxt_scantuple correctly for tuple routing.

In 2ac3ef7a01df859c62d0a02333b646d65eaec5ff, we changed things so that
it's possible for a different TupleTableSlot to be used for partitioned
tables at successively lower levels.  If we do end up changing the slot
from the original, we must update ecxt_scantuple to point to the new one
for partition key of the tuple to be computed correctly.

Reported by Rajkumar Raghuwanshi.  Patch by Amit Langote.

Discussion: http://postgr.es/m/CAKcux6%3Dm1qyqB2k6cjniuMMrYXb75O-MB4qGQMu8zg-iGGLjDw%40mail.gmail.com

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/132488bfee687865375b5410f18a78fb55bd7015

Modified Files
--------------
src/backend/catalog/partition.c      | 30 +++++++++++++++++++++++-------
src/backend/executor/execMain.c      |  2 --
src/test/regress/expected/insert.out |  2 +-
src/test/regress/sql/insert.sql      |  2 +-
4 files changed, 25 insertions(+), 11 deletions(-)