Fix parallel-engine crash on Windows when using transparency in SR mode. The culprit was an MPI_Allreduce with MPI_UNSIGNED_LONG_LONG. The call aborted the mpi tasks because MPI_MAX is not defined for this datatype with the msmpi we currently use on Windows. The call was modified to use MPI_UNSIGNED_LONG instead.
git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@31540 18c085ea-50e0-402c-830e-de6fd14e8384