Only log remote nameservers

Skip the A/AAAA records.

Previously, we would log:
Unable to find backend willing to host example.com for potential supermaster x.x.x.x. 4 remote nameservers:
test1.example.com
test2.example.com
x.x.x.x
x.x.x.y
Merge pull request #1946 from rubenk/only-log-nameservers

Only log remote nameservers