Follow-up from "Fix compile time warning from !1118"

The following discussion from !1130 (merged) should be addressed:

• @graven started a discussion: (+1 comment)

  can we please, instead of having a loop with an 'if and break' construction just use std::find_if, and avoid first initializing and then overwriting a local variable?

          auto i = std::find_if( m_handles.begin(), m_handles.end(), [](const auto& data) { return data.mode() == Gaudi::DataHandle::Writer && data.objKey() == "Renounce" ; } );
          const DataObjID* renounce_id = ( i != m_handles.end() ?  &(i->fullKey()) : nullptr;

  and even better, properly deal with the fact that as-is, renounce_id may be a nullptr, and thus L130 will SEGV, and thus is would be better to put that code inside

  auto i = std::find_if( m_handles.begin(), m_handles.end(), [](const auto& data) { return data.mode() == Gaudi::DataHandle::Writer && data.objKey() == "Renounce" ; } );
  if ( i!= m_handles.end() ) {
     TestTool::Logger          logger;
     RenounceToolInputsVisitor renouncer( std::vector<DataObjID>( {i->fullKey()} ), logger );
     DEBUG_TRACE( std::cout << "DEBUG " << name() << " renounce tools "
                                 << "Renounce" << std::endl );
     ToolVisitor::visit( tools(), renouncer );
  
  }

  I know this is 'just' test code, but I would still prefer a more idiomatic, clearer style even there...