util/djbhash: simplify the formula, multiplication instead of shift/add
util/djbhash: simplify the formula, multiplication instead of shift/add

The GCC will happily optimize this for us.

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy