Removed Malte's "fix" to content-folder::new, and emmanuelle's fix to that
fix (which was fine), reverting to the 5.3 version because it wasn't broken
in the first place, and malte's attempt removed transaction protection
around the folder inserts (bad!) in order to avoid a pg-only deadlock in
PG 8.1 which doesn't happen in PG 8.2 or better.