Genereate /etc/os-release during build_image

os-release fields can be set through /etc/os-release.d so we need to rebuild
os-release when building the image.

BUG=chromium:420784
TEST=Set a field in /etc/os-release.d. The image contains that field in
/etc/os-release.

CQ-DEPEND=CL:221761

Change-Id: I5f734323f16ea1ebcdd14fd12d32b46ff9ba3367
Reviewed-on: https://chromium-review.googlesource.com/221756
Commit-Ready: Andrey Ulanov <andreyu@google.com>
Tested-by: Andrey Ulanov <andreyu@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed