[PATCH 3 of 3] commit: try hard to reuse p1 manifest if nothing changed

[Augie Fackler]

> On Aug 14, 2018, at 8:47 PM, Yuya Nishihara <yuya at tcha.org> wrote:
> 
> # HG changeset patch
> # User Yuya Nishihara <yuya at tcha.org>
> # Date 1530970839 -32400
> #      Sat Jul 07 22:40:39 2018 +0900
> # Node ID ed903661203305cb8c0d44f420aa3ace06c4f46e
> # Parent  242bf65ae76ad839d89dbae348eec5f28990b663
> commit: try hard to reuse p1 manifest if nothing changed

queued, thanks