message: prevent name bids on invalid account names or on account names that do not need bids
diff: @@ -97,6 +97,9 @@ namespace eosiosystem {
  void system_contract::bidname( account_name bidder, account_name newname, asset bid ) {
  require_auth( bidder );
  eosio_assert( eosio::name_suffix(newname) == newname, "you can only bid on top-level suffix" );
  + eosio_assert( newname != 0, "the empty name is not a valid account name to bid on" );
  + eosio_assert( (newname & 0xFull) == 0, "13 character names are not valid account names to bid on" );
  + eosio_assert( (newname & 0x1F0ull) == 0, "accounts with 12 character names and no dots can be created without bidding required" );
  eosio_assert( !is_account( newname ), "account already exists" );
  eosio_assert( bid.symbol == asset().symbol, "asset must be system token" );
  eosio_assert( bid.amount > 0, "insufficient bid" );
  