Remove unused function parameters, part 1: contrib

Hi hackers,

PFA patches to remove unused function parameters in contrib (more patches will
come for non contrib).

The patches are split by modules to ease the review.

For 0005 (collid not used in internal_citext_pattern_cmp()) I think that the
unused column should be used (as done in 0005) due to an oversight in commit
f2464997644c.

This has been done with the help of a coccinelle script. It needs more polishing,
so will share later.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com