Test 6fb4 creates one mirred and one pipe action, but only flushes mirred
on teardown. Leaking pipe action causes failures in other tests.

Add additional teardown command to also flush gact actions.
Signed-off-by: NVlad Buslov <vladbu@mellanox.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>