netsched: Allow var_sk_bound_if meta to work on all namespaces

This fix can probably wait 2.6.33, or should use another patch
if needed in 2.6.32 (no get_dev_by_index_rcu() before 2.6.33)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>