remove unnecessary call to make_image_bootable for dev recovery

remove unnecessary call to make_image_bootable for dev recovery

Change-Id: I43f88cbe4df74e254299a95c5e1b62a300230385

Undo part of commit by drewry
http://chromiumos-git/?p=crosutils.git;a=commit;h=7ab698d713bcad066f0ee0469fbbcaa274411d08

mod_image_for_dev_recovery.sh modifies a dev install shim image (already
bootable) by altering content of its stateful partition. The result image does
NOT need to be made bootable again.

TEST=manually built a dev recovery image (based on a factory install shim) and
verified recovery functionality on agz device with cros fw

[Tan Gao, 2010-08-05 23:26:21]

Hi Will,

This CL undoes part of change in  http://codereview.chromium.org/3066037 so that
dev recovery image continues to work :-)

PTAL thx!
Tan

[Will Drewry, 2010-08-06 00:19:42]

LGTM, but with a question :)

Cool - this seems fine to me but it raises a bigger question.

.dev_recovery and .recovery live on the stateful partition.  Do they result in
any changes in a normal bootflow?  If so, they need to live on the rootfs so
that they can't be used against our production image.  I'm not sure what they do
though so maybe it's a non-issue!

thanks!
will

[Tan Gao, 2010-08-06 00:25:02]

Good question! Nope, neither affects the normal boot flow. These *magic* files
are used solely for recovery purpose and should NOT appear on hard drive of a
device, ever (if either did some whatever reason, we would be in bigger trouble
:-)

[Will Drewry, 2010-08-06 00:47:16]

On Thu, Aug 5, 2010 at 7:25 PM,  <tgao@chromium.org> wrote:
> Good question! Nope, neither affects the normal boot flow. These *magic*
> files
> are used solely for recovery purpose and should NOT appear on hard drive of
> a
> device, ever (if either did some whatever reason, we would be in bigger
> trouble
> :-)

So if a user managed to touch either of those magic file in their
stateful, what would happen?  Given that we don't verify the stateful
data, we have to assume the user or an attacker could modify it, so
it's crucial that we don't change the system behavior too
dramatically!

[Tan Gao, 2010-08-06 00:50:49]

Agreed! the entire recovery feature needs to go through some sort of security
review at some point to carefully consider all these potential attack scenarios
:-)

[Will Drewry, 2010-08-06 01:01:04]

Soo, what do the magic files do?

On Thu, Aug 5, 2010 at 7:50 PM,  <tgao@chromium.org> wrote:
> Agreed! the entire recovery feature needs to go through some sort of
> security
> review at some point to carefully consider all these potential attack
> scenarios
> :-)
>
> http://codereview.chromium.org/3074037/show
>