build_image: Remove unused advanced flags

Remove the --app_id and --extra_packages advanced flags to build_image,
which are no longer going to be used.

BUG=chromium:507509
TEST=./build_image --board=panther
TEST=./build_image --board=panther --noenable_rootfs_verification test

Change-Id: Ic5055fa7563e2be840201fee31f888ca426d05e1
Reviewed-on: https://chromium-review.googlesource.com/284109
Tested-by: Steve Fung <stevefung@chromium.org>
Reviewed-by: David Pursell <dpursell@chromium.org>
Commit-Queue: Steve Fung <stevefung@chromium.org>
Trybot-Ready: Steve Fung <stevefung@chromium.org>
2 files changed