CLEANUP: resolvers: get rid of single-iteration loop in resolv_get_ip_from_response()

CLEANUP: resolvers: get rid of single-iteration loop in resolv_get_ip_from_response()

In issue 1424 Coverity reports that the loop increment is unreachable,
which is true, the list_for_each_entry() was replaced with a for loop,
but it was already not needed and was instead used as a convenient
construct for a single iteration lookup. Let's get rid of all this
now and replace the loop with an "if" statement.