Description of problem:

As described at https://gitlab.labs.nic.cz/labs/knot/issues/493
knotd when HUP-reloading tries to load the original symlink's destination, not the default file.

There is a patch to be included in the next release. AFAICT, there is no schedule yet on when that might be. Can you include the patch directly?

Version-Release number of selected component (if applicable):
> knotd --version
Knot DNS, version 1.6.8
> rpm -q knot
knot-1.6.8-1.el7.x86_64

How reproducible:
always

Steps to Reproduce:
sh-4.2$ # knot.conf is a valid config file
sh-4.2$ cd /tmp/
sh-4.2$ mkdir orig
sh-4.2$ mv knot.conf orig/
sh-4.2$ ln -s orig/knot.conf .
sh-4.2$ vi knot.conf 
sh-4.2$ knot^C
sh-4.2$ mkdir new^C
sh-4.2$ mv orig new
sh-4.2$ ln -fs new/knot.conf .
sh-4.2$ kill -HUP 113

With the following knotd output (logging to stderr).

sh-4.2$ knotd -c /tmp/knot.conf 
Warning: log severity 'all' is no longer supported. Using 'info' instead.
2016-12-19T13:15:33 info: Knot DNS 1.6.8 starting
2016-12-19T13:15:33 info: binding to interface '0.0.0.0@53536'
2016-12-19T13:15:33 info: binding to interface '::@53536'
2016-12-19T13:15:33 info: configured 2 interfaces and 0 zones
2016-12-19T13:15:33 info: loading zones
2016-12-19T13:15:33 warning: no zones loaded
2016-12-19T13:15:33 info: starting server
2016-12-19T13:15:33 info: server started in the foreground, PID 113
2016-12-19T13:15:33 info: binding remote control interface to '/tmp/knot/knot.sock'
2016-12-19T13:16:14 info: reloading configuration
2016-12-19T13:16:14 error: configuration file '/tmp/orig/knot.conf' not found