Add lockfile-progs to dependencies.

Required since 3e9aca9c0795a205b4afe069ddd403889b95ffd2.
Merge branch 'add-lockfile-progs-to-packages' into rails-3-develop
Merge branch 'rails-3-develop' of ssh://git.mysociety.org/data/git/public/alaveteli into rails-3-develop