Added ovs-vsctl commands of QoS-related

Here is added the command of QoS-related, such as the following:

ovs-vsctl -- set port eth1 qos=@newqos \
 -- --id=@newqos create qos type=linux-htb other-config:max-rate=30000000 queues=0=@q0,1=@q1 \
 -- --id=@q0 create queue other-config:min-rate=1000000 other-config:max-rate=1000000 \
 -- --id=@q1 create queue other-config:min-rate=2000000 other-config:max-rate=2000000

Also, operation that delete QoS is supported.
Note that It supports only deletion of relationships with QoS record.

Signed-off-by: Kiyonari Harigae <lakshmi@cloudysunny14.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Added queue stats request

Here is added queue status request to ofctl.

Signed-off-by: Kiyonari Harigae <lakshmi@cloudysunny14.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>