Update PCR state with the state of the firmware keyblock flags too.

I re-factored the extend call into its own module, since it doesn't necessarily
need to be couple with rollbackfirmwaresetup.

BUG=chrome-os-partner:2372
TEST=Tried emerge-x86-generic and emerge-arm-generic vboot_reference.

Change-Id: I0d3115b10b686133e63e304570325ebdbd50ae3a

Review URL: http://codereview.chromium.org/6696006
8 files changed