pgsql: Remove duplicate words in comments.

Remove duplicate words in comments.

Found these with grep -r "for for ".

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f291ccd43e06fdd7c55102975a0b2f38bc140b90

Modified Files
--------------
src/backend/access/spgist/spgdoinsert.c |    2 +-
src/backend/storage/ipc/standby.c       |    2 +-
src/backend/tcop/postgres.c             |    2 +-
src/backend/utils/adt/numeric.c         |    2 +-
src/include/tsearch/dicts/regis.h       |    2 +-
5 files changed, 5 insertions(+), 5 deletions(-)