[tor-relays] log: DNS servers not contactable (but only for a few seconds)

[Zenaan Harkness]

Notwithstanding the short DNS outage as shown in the logs, I added a
couple of extra Australian DNS servers to resolv.conf since previously
I only had the primary and secondary DNS servers as assigned by the
ISP.

Just wondering if there's anything else I should do to increase
robustness on this front.

TIA
Zenaan