Improve database performance for partial indexes on boolean columns (bug 587028 in...

Improve database performance for partial indexes on boolean columns (bug 587028 in Launchpad)

PostgreSQL 8.3/8.4 treats "IS FALSE" and "= FALSE" expressions differently,
which can have a significant impact on database performance if an index is
created with one and a query uses the other. This patch addresses all existing
partial indexes on boolean columns to enable the query planner to use an index
scan whether the query uses either expression.

Thanks to James Fournie of BC Sitka for noticing the problem with the index
on asset.copy and opening bug 587028 in Launchpad with the suggested fix!

git-svn-id: svn://svn.open-ils.org/ILS/trunk@16588 dcc99617-32d9-48b4-a31d-7c20da2025e4