Add dependency on resolvconf
The latest version of the fw depends on resolvconf to be present on the system. Debian package should add the strict dependency (now is suggests), and we should document it's a hard-dep for the bundle too.
If we don't want it to be a hard-dep, we could do a workaround using the old resolv-update hackery.
(from redmine: created on 2014-05-07, closed on 2014-06-10, precedes #5588 (closed))