Return DoS state for missing inputs in name tx.
Return DoS state for missing inputs in name tx.

When a name transaction is invalid because the name input cannot be
fetched, return a DoS error instead of just Invalid.  This matches the
behaviour for non-name transactions in this case and fixes the broken
feature_block.py regtest (which now expects such transactions to
disconnect the peer).

namecoin/namecore,pataquets/namecoin-core,domob1812/namecore,domob1812/namecore,domob1812/namecore,namecoin/namecore,domob1812/namecore,domob1812/namecore,namecoin/namecoin-core,pataquets/namecoin-core,domob1812/namecore,pataquets/namecoin-core,pataquets/namecoin-core,namecoin/namecore,namecoin/namecore,pataquets/namecoin-core,namecoin/namecoin-core,namecoin/namecoin-core,namecoin/namecoin-core,namecoin/namecoin-core,namecoin/namecore,pataquets/namecoin-core,namecoin/namecore,namecoin/namecoin-core