pgsql: Process withCheckOption exprs in setrefs.c

Process withCheckOption exprs in setrefs.c

While withCheckOption exprs had been handled in many cases by
happenstance, they need to be handled during set_plan_references and
more specifically down in set_plan_refs for ModifyTable plan nodes.
This is to ensure that the opfuncid's are set for operators referenced
in the withCheckOption exprs.

Identified as an issue by Thom Brown

Patch by Dean Rasheed

Back-patch to 9.4, where withCheckOption was introduced.

Branch
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REL9_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/c4bee09c0e1fc7fb2281ba1e125ab17c5e9a20e7

Modified Files
--------------
src/backend/optimizer/plan/setrefs.c | 3 +++
src/test/regress/expected/updatable_views.out | 20 ++++++++++++++++++++
src/test/regress/sql/updatable_views.sql | 19 +++++++++++++++++++
3 files changed, 42 insertions(+)