read-tree --aggressive: remove deleted entry from the working tree.

When both heads deleted, or our side deleted while the other
side did not touch, we did not have to update the working tree.

However, we forgot to remove existing working tree file when we
did not touch and the other side did.

Signed-off-by: Junio C Hamano <junkio@cox.net>

read-tree.c

@@ -560,9 +560,11 @@ static int threeway_merge(struct cache_entry **stages)
 		 */
 		if ((head_deleted && remote_deleted) ||
 		    (head_deleted && remote && remote_match) ||
-		    (remote_deleted && head && head_match))
+		    (remote_deleted && head && head_match)) {
+			if (index)
+				return deleted_entry(index, index);
 			return 0;
-
+		}
 		/*
 		 * Added in both, identically.
 		 */