message: Update get_blockchain_parameters_packed for gh#2132
diff: @@ -155,14 +155,18 @@ class privileged_api : public context_aware_api {
  });
  }
  - uint32_t get_blockchain_parameters_packed( array_ptr<char> packed_blockchain_parameters, size_t datalen) {
  + uint32_t get_blockchain_parameters_packed( array_ptr<char> packed_blockchain_parameters, size_t buffer_size) {
  auto& gpo = context.controller.get_global_properties();
  - auto size = fc::raw::pack_size( gpo.configuration );
  - if ( size <= datalen ) {
  - datastream<char*> ds( packed_blockchain_parameters, datalen );
  +
  + auto s = fc::raw::pack_size( gpo.configuration );
  + if( buffer_size == 0 ) return s;
  +
  + if ( s <= buffer_size ) {
  + datastream<char*> ds( packed_blockchain_parameters, s );
  fc::raw::pack(ds, gpo.configuration);
  + return s;
  }
  - return size;
  + return 0;
  }
  