[Github Issue] modify init script to properly use rundir in /etc/config/resolver
#### **DO NOT EDIT HERE!** Copy from https://github.com/CZ-NIC/turris-os-packages/issues/46
please add this changes to turris-os-repo it will properly use the 'rundir' specified in /etc/config/resolver in the /etc/init.d/knotd init script and also make the hints file and tty point to it.
it actually makes it possible to use a different rundir from /etc/config/resolver fully. At the moment the init script only uses rundir partially. I always had to also change the init script (apart from /etc/config/resolver) and manually change the DEFAULT_RUNDIR the and the tty file (which is hardcoded) to point to the new rundir. Problem my changes always got overwritten with each and every new release.