Program to create bootcache area

Changes to bootcache program to match changes that have been
made to the bootcache device mapper.

BUG=chromium-os:25441
TEST=created bootcache and booted system.

Change-Id: Idc62d4cea72d69f4c202460400219184916231ee
Reviewed-on: https://gerrit.chromium.org/gerrit/31761
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
Commit-Ready: Paul Taysom <taysom@chromium.org>
Tested-by: Paul Taysom <taysom@chromium.org>
3 files changed