message: use C++11 range based for loop in parallel.cpp
diff: @@ -669,7 +669,7 @@ void HandleBlockMessageThread(CNode *pfrom, const string strCommand, CBlockRef p
  }
  // Count up any other remaining nodes with graphene blocks in flight.
  - BOOST_FOREACH (CNode *pnode, vNodes)
  + for (CNode *pnode : vNodes)
  {
  if (pnode->mapGrapheneBlocksInFlight.size() > 0)
  nTotalGrapheneBlocksInFlight++;
  