Return a name error by the resolver when the referenced name does not exist

[NotBad4U]

According to rfc1034, when a resolver performs a lookup on a referenced name which does not exist, a name error must be return.

When the resolver performs the indicated function, it usually has one of
the following results to pass back to the client:

   - One or more RRs giving the requested data.

     In this case the resolver returns the answer in the
     appropriate format.

   - A name error (NE).
   ^^^^^^^^^^^^^^^^^^^^^^

     This happens when the referenced name does not exist.  For
     example, a user may have mistyped a host name.
    ^^^^^^^^^^^^^^^^^^^^^^
   - A data not found error.