Subdiv: CCG, fix memory leak

Forgot to free memory used by grid to face mapping array.

source/blender/blenkernel/intern/subdiv_ccg.c

@@ -428,6 +428,7 @@ void BKE_subdiv_ccg_destroy(SubdivCCG *subdiv_ccg)
 		BKE_subdiv_free(subdiv_ccg->subdiv);
 	}
 	MEM_SAFE_FREE(subdiv_ccg->faces);
+	MEM_SAFE_FREE(subdiv_ccg->grid_faces);
 	MEM_freeN(subdiv_ccg);
 }