apparmor: take nosymfollow flag into account

A "nosymfollow" flag was added in commit
dab741e0

 ("Add a "nosymfollow" mount option.")

While we don't need to implement any special logic on
the AppArmor kernel side to handle it, we should provide
user with a correct list of mount flags in audit logs.

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>