 Fix CMakeLists for when not using mpi.
 Fix CMakeLists for when not using mpi.

rbaghdadi/tiramisu,rbaghdadi/tiramisu,rbaghdadi/ISIR,rbaghdadi/tiramisu,rbaghdadi/tiramisu,rbaghdadi/COLi,rbaghdadi/ISIR,rbaghdadi/COLi