pgsql: Put static forward declarations in elog.c back into same order a

Put static forward declarations in elog.c back into same order as code.

The guiding principle for the last few patches in this area apparently
involved throwing darts.

Cosmetic only, but back-patch to 9.6 because there is no reason for
9.6 and HEAD to diverge yet in this file.

Branch
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REL9_6_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/42ebdc8129f038e06e17d7b3da7fc11897323814

Modified Files
--------------
src/backend/utils/error/elog.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)