Enhance 'cgpt find' command to match keyblocks if desired.

This is part of the proposed developer-mode installation process, where we
want to detect that whoever is fiddling with the hard drive has already
fiddled with it before. Otherwise, we'll make them wait a bit to prevent
drive-by updates.

BUG=chromium-os:5306

Change-Id: Ifd6dce69180fa818fe14dbc3b1ac3485fb15d1c9

Review URL: http://codereview.chromium.org/3122023
4 files changed