clean up excessive output printed by mod_image_for_dev_recovery

clean up excessive output printed by mod_image_for_dev_recovery

Change-Id: I8d04a04ad75f8cd5b040572ac6bb16e594d59e0e

TEST=manually built a dev recovery image and tested in agz device to verify
it installed payload image onto the target and the target is able to boot from HD

[Tan Gao, 2010-09-22 23:17:20]

Hi Andrew,

This CL cleans up output generated by mod_image_for_dev_recovery.sh and
correctly cleans up temp files/dirs after script exits. PTAL

thx!
Tan

[adlr, 2010-09-23 18:00:59]

http://codereview.chromium.org/3432017/diff/1/2
File mod_image_for_dev_recovery.sh (right):

http://codereview.chromium.org/3432017/diff/1/2#newcode83
mod_image_for_dev_recovery.sh:83: local loop_dev=$1
i would actually keep this function the same. Right now if you accidentally call
it twice, it will first free up the loop device that you allocated, and the
second time it will either: provide no error/warning you've called it a second
time OR free up the loop device allocated by someone else. It seems better to
have a warning if you accidentally call it twice so that it can be fixed.

http://codereview.chromium.org/3432017/diff/1/2#newcode121
mod_image_for_dev_recovery.sh:121: 
here, too:
trap - EXIT
umount_from_loop_dev ${temp_mnt} && cleanup_loop_dev ${loop_dev}

http://codereview.chromium.org/3432017/diff/1/2#newcode195
mod_image_for_dev_recovery.sh:195: 
i think the usual pattern is right here you should do:
trap - EXIT
umount_from_loop_dev ${temp_mnt} && cleanup_loop_dev ${loop_dev}

[Tan Gao, 2010-09-23 21:25:15]

http://codereview.chromium.org/3432017/diff/1/2
File mod_image_for_dev_recovery.sh (right):

http://codereview.chromium.org/3432017/diff/1/2#newcode83
mod_image_for_dev_recovery.sh:83: local loop_dev=$1
good call. simplified

http://codereview.chromium.org/3432017/diff/1/2#newcode121
mod_image_for_dev_recovery.sh:121: 
On 2010/09/23 18:00:59, adlr wrote:
> here, too:
> trap - EXIT
> umount_from_loop_dev ${temp_mnt} && cleanup_loop_dev ${loop_dev}

Done.

http://codereview.chromium.org/3432017/diff/1/2#newcode195
mod_image_for_dev_recovery.sh:195: 
On 2010/09/23 18:00:59, adlr wrote:
> i think the usual pattern is right here you should do:
> trap - EXIT
> umount_from_loop_dev ${temp_mnt} && cleanup_loop_dev ${loop_dev}

Done.

[adlr, 2010-09-23 21:37:42]

LGTM thanks!