Port `bin/delete-version` to use Diesel
Port `bin/delete-version` to use Diesel

The changes here were broadly similar to those in `delete-crate`. The
child row deletions are no longer needed here, as they cascade in the
database. (Arguably neither of these binaries are really needed anymore
since it can just be done in the database)

rust-lang/crates.io,rust-lang/crates.io,steveklabnik/crates.io,steveklabnik/crates.io,rust-lang/crates.io,steveklabnik/crates.io,rust-lang/crates.io,steveklabnik/crates.io