Fix redundant redrawing in Pegs. Apparently it has always redrawn

every single peg and hole on the board, every time it did any kind of
redraw at all, because I forgot to update the array in the drawstate
indicating the last-drawn state of each position. And nobody's noticed
until now!

[originally from svn r9447]

pegs.c

@@ -1237,6 +1237,7 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
                 (bgcolour != ds->bgcolour || /* always redraw when flashing */
                  v != ds->grid[y*w+x])) {
 		draw_tile(dr, ds, COORD(x), COORD(y), v, bgcolour);
+                ds->grid[y*w+x] = v;
 	    }
 	}