libev/c-ares migration: unstack out ouf c-ares before querying new requests

libev/c-ares migration: unstack out ouf c-ares before querying new requests

  - we use the c-ares callback to parse the DNS reply and put the reply to our callback
  - we then set a zero-timer with the call to continue our flow
  - we return / unstack c-ares
  - we then do the a/aaaa record lookup without having another ares lookup in our stack
this circumvents double dns lookups.