Update stateful size calculation in mod_image_for_recovery

The default size calculated for stateful in mod_image_for_recovery.sh
wasn't leaving enough space for logs.  Adjust the calculation to be
more generous.

This also changes the meaning of the --statefulfs_sectors option
to be more useful by providing a minimum numbmer of free sectors,
rather than a minimum total sectors.

BUG=chromium:469195
TEST=Mount stateful from a recovery image, check free space

Change-Id: If7e86b52bc630b3cb76326e583d98eede30fac05
Reviewed-on: https://chromium-review.googlesource.com/261943
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
1 file changed