Revert "Fix thinko in commit 3005c906292700799f236fa04c44dbfbdb5ba734."

This reverts commit 8b051df8c8bc120b30f797464aa6c4d747eaf2df. This breaks
the XactComit hook for PostgreSQL 9.3. Somehow i missed that during my
analysis earlier.
Right fix for commit 3005c906292700799f236fa04c44dbfbdb5ba734.