Actually resolve all IPs for Private DNS hostname

Previously, we reused the OneAddressPerFamilyNetwork which does
what it says on the tin.  For the resolution that will be used
to program netd this is not what we really want.

Test: as follows
    - built
    - flashed
    - booted
    - runtest frameworks-net passes
    - manual testing of Private DNS passes
Bug: 64133961
Change-Id: Ieccc4d208b314b81061dc78d83848f97acefe04b