Update octree_pointcloud_voxelcentroid.hpp

line 51 : OctreePointCloudVoxelCentroidContainer<PointT>* leaf; instead of LeafNode* to avoid compilation error
LeafNode should be defined: [pcl/octree/octree_pointcloud_voxelcentroid.h](https://github.com/ThomasGuerneve/pcl/blob/patch-1/octree/include/pcl/octree/octree_pointcloud_voxelcentroid.h#L153)