permission: add xt_qtaguid file permession checks.

In the past, the xt_qtaguid netfilter would auto-init the groups allowed
to access and control its data based on AID_NET_BW_ACCT and
AID_NET_BW_STATS. But now, it relies on file group ownership to get those
group IDs. They should be setup in init.rc.

Change-Id: I5d1ddc07eb6d1c31510bea2875076e930bd0039d