-DMPIEXEC=/usr/local/mpi/openmpi/bin/mpiexec doesn't make VTK to link with OpenMPI, it still links with mpich when it is installed
-- Found MPI_C: /usr/local/lib/libmpi.so
-- Found MPI_CXX: /usr/local/lib/libmpicxx.so;/usr/local/lib/libmpi.so
-- Found MPI_C: /usr/local/lib/libmpi.so
-- Found MPI_CXX: /usr/local/lib/libmpicxx.so;/usr/local/lib/libmpi.so