pgsql: Remove unnecessary include

Remove unnecessary include

Between 6eeb95f0f56bb5e8a0a9328aeec04c9e6de87272 and
7b1c2a0f2066672b24f6257ec9b8d78a1754f494, builtins.h contained
additional prototypes that have now been moved elsewhere, so we don't
need to include nodes/parsenodes.h anymore.

Fix some files that were relying on builtins.h implicitly pulling in
some unrelated stuff they needed.

Reviewed-by: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/30b9a4495a8ec1f20ba518b34d679c700eadab16

Modified Files
--------------
src/backend/catalog/pg_enum.c | 1 +
src/backend/utils/adt/oid.c | 1 +
src/include/utils/builtins.h | 1 -
3 files changed, 2 insertions(+), 1 deletion(-)