pgsql: Fix bogus comment.

Fix bogus comment.

Commit 4212cb73262bbdd164727beffa4c4744b4ead92d rendered a comment
in execMain.c incorrect.  Per complaint from Tom Lane, repair.

Patch from Amit Kapila, per wording suggested by Tom Lane and me.

Branch
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REL9_6_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/86c6aaff6ead3e00a89fd0743195678bbc69790c

Modified Files
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src/backend/executor/execMain.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)