update_kernel: Don't make fake bootloader stub in 'latest'

The build_image script isn't able to overcome the fact that
update_kernel.sh makes a non-symlink directory for 'latest' in the
images directory when it makes a fake bootloader stub. Usually this
isn't a problem because developers build an image first and then
update_kernel from it, but if you build an image after running
update_kernel you'll see that it fails to build the image when trying to
repoint the 'latest' symlink.

Make a bootloader stub in /tmp instead and remove it when we're done to
avoid this problem.

TEST=update_kernel to DUT without image, build_image after and see it

Change-Id: I28b87dafb0af7b73151875053a55857d74dfa1d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2029135
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
1 file changed