selinux: allow getattr for brillo_setup

It seems something may have changed with bash to start needing getattr
to run scripts. This was causing initnetwork.sh to fail, which also
needed its "route" command changed to "ip route" since "route" is missing
too now.

Bug: 28864097

Change-Id: Ieedd9c282cd95c9e207e13b082ea65e92bea8f4f
5 files changed