[ticket/12515] Remove check for PostgreSQL 8.3+

PHPBB3-12515
Merge pull request #2654 from nickvergessen/ticket/12515

[ticket/12515] Remove check for PostgreSQL 8.3+ in search

* nickvergessen/ticket/12515:
  [ticket/12515] Remove check for PostgreSQL 8.3+
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12515] Remove check for PostgreSQL 8.3+