After NM introduced dns-change event, we are creating an infinite loop of on-prem-resolv-prepender.service runs. This is because our prepender script ALWAYS runs `nmcli general reload dns-rc`, no matter if the changes are needed for real or not.

Because of this, we have the following

1) NM change DNS
2) dispatcher script append a server to /etc/resolv.conf
3) dispatcher invoked again as new dns-change event.
4) dispatcher check again and creates new /etc/resolv.conf, the same as old
5) NM change DNS, dns-change event is invoked
6) goto 3

As a fix, prepender script should check if the newly generated file differs from existing /etc/resolv.conf and only apply change if needed.