Fixing coverty errors

src/Graph/CartesianGraphFactory.hpp

src/Grid/grid_sm.hpp

src/NN/CellList/CellDecomposer.hpp

src/NN/CellList/CellList.hpp

src/NN/CellList/CellNNIterator.hpp

src/NN/CellList/CellNNIteratorRuntime.hpp

src/NN/CellList/cuda/Cuda_cell_list_util_func.hpp

src/NN/VerletList/VerletListFast.hpp

src/Space/Shape/HyperCube.hpp

src/Space/Shape/Point.hpp

src/util/compute_optimal_device_grid.hpp