Reverting "use celery's task dependency management to chain and parallelize reindexing. (bug 867289)"
Reverting "some missed celery calls"

This reverts commits 3d91a0ae132ef5601f1e8f35dd7cce4d6e9d4eb2 and
164d41e4b6678bafbc0b12a141643ce812ed9678.