lidarlib: free structs

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@71191 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/lidar/zones.c

@@ -294,6 +294,9 @@ double P_estimate_splinestep(struct Map_info *Map, double *dens, double *dist)
 	    }
 	}
     }
+    Vect_destroy_cats_struct(categories);
+    Vect_destroy_line_struct(points);
+
     if (npoints > 0) {
 	/* estimated average distance between points in map units */
 	*dist = sqrt(((xmax - xmin) * (ymax - ymin)) / npoints);