rerere: do not skip two conflicted paths next to each other.

The code forgot to take the for (;;) loop control into account,
incrementing the index once too many.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

builtin-rerere.c

@@ -160,7 +160,7 @@ static int find_conflict(struct path_list *conflict)
 				ce_stage(e3) == 3 && ce_same_name(e1, e2) &&
 				ce_same_name(e1, e3)) {
 			path_list_insert((const char *)e1->name, conflict);
-			i += 3;
+			i += 2;
 		}
 	}
 	return 0;