[PATCH 1 of 7] verify: move checklog() onto class

[Durham Goode]

On 1/5/16 6:44 PM, Durham Goode wrote:
> # HG changeset patch
> # User Durham Goode <durham at fb.com>
> # Date 1452042494 28800
> #      Tue Jan 05 17:08:14 2016 -0800
> # Node ID 0886e38814dbc6f305102fa89203ee4d53b0874d
> # Parent  b8405d739149cdd6d8d9bd5e3dd2ad8487b1f09a
> verify: move checklog() onto class
>
> This is part of an effort to make verify more modular so extensions can hook
> into it.
>
This is the second (and final) series in my refactor of verify to be 
inside a class.  It makes verify more extensible for extensions to hook 
in to.