apparmor: fix dbus permission queries to v9 ABI

dbus permission queries need to be synced with fine grained unix
mediation to avoid potential policy regressions. To ensure that
dbus queries don't result in a case where fine grained unix mediation
is not being applied but dbus mediation is check the loaded policy
support ABI and abort the query if policy doesn't support the
v9 ABI.

Signed-off-by: John Johansen <john.johansen@canonical.com>