The factory software has tried to inhibit arc-system-mount service in factory/init/common.d/inhibit_jobs/arc-system-mount.

However, since CL:*411369, arc-system-mount.conf has been changed from "start on started" to "start on starting boot-services", same priority and timing as factory-init.

As a result, factory-init has no time to install the inhibit script and arc-system-mount will be started.

Currently there's no much problems, but in future we may see problems like "can't finalize due to mounted arc-system-mount" or "unexpected or extra arc services started and cause system to be pretty slow".

Should figure out some better way to disable services.

This should be low priority until we see real problems.