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: Junio C Hamano <junkio@cox.net>
diff --git a/builtin-rerere.c b/builtin-rerere.c
index 318d959..ac0bf33 100644
--- a/builtin-rerere.c
+++ b/builtin-rerere.c
@@ -160,7 +160,7 @@
 				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;