apparmor: fix setting unconfined mode on a loaded profile

When loading a profile that is set to unconfined mode, that label
flag is not set when it should be. Ensure it is set so that when
used in a label the unconfined check will be applied correctly.

Fixes: 03816507 ("apparmor: allow setting any profile into the unconfined state")
Signed-off-by: John Johansen <john.johansen@canonical.com>