cros_generate_update_payload: Don't mount src/dst rootfs.

The delta_generator doesn't require us to pass the mounted rootfs
anymore so we avoid mounting them from cros_generate_update_payload.
Note that mounting the stateful partition is still required for old
images with an unpatched kernel.

This patch also runs delta_generator as a normal user since it doesn't
access the mounted filesystems anymore which were the only files
requiring root.

TEST=Ran cros_generate_update_payload delta on old (link FSI) and new (link ToT) images.

Change-Id: I5cc0dd8666bbf374a9b04a43b5713c62e9718821
Reviewed-by: Mike Frysinger <>
Reviewed-by: Don Garrett <>
Tested-by: Alex Deymo <>
Trybot-Ready: Alex Deymo <>
Commit-Queue: Alex Deymo <>
1 file changed