use crossystem for developer mode and nonchrome detection

use crossystem for developer mode and nonchrome detection

Adds crossystem use for developer mode detection and nonchrome detection.
[This allows systems with missing or damaged TPMs or bad firmware to
 go through recovery as nonchrome systems.]

(testing in progress)
TEST=create a devkeys x86-alex image, boot it and install it in both modes
     same thing for x86-mario
     boot x86-mario, goto a shell, run crossystem mainfw_act to ensure it never says nonchrome
     again for a nonchrome system
BUG=chromium-os:13399, chromium-os:8762
Change-Id: I538fe37fbed29537132da15c844b75ce726634bf

R=gauravsh@chromium.org

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=28966b0

[gauravsh, 2011-03-23 02:25:18]

LGTM with a comment

http://codereview.chromium.org/6724018/diff/1/init
File init (right):

http://codereview.chromium.org/6724018/diff/1/init#newcode576
init:576: crossystem mainfw_type?nonchrome
it wasn't clear to me what exactly this does. Does crosystem return 0 (i.e .
succed) if mainfwtype=='nonchrome'?

[Randall Spangler, 2011-03-23 15:54:17]

http://codereview.chromium.org/6724018/diff/1/init
File init (right):

http://codereview.chromium.org/6724018/diff/1/init#newcode576
init:576: crossystem mainfw_type?nonchrome
On 2011/03/23 02:25:18, gauravsh wrote:
> it wasn't clear to me what exactly this does. Does crosystem return 0 (i.e .
> succed) if mainfwtype=='nonchrome'?

Yes.  (New feature of crossystem)