datapath: Avoid using wrong metadata for recic action.

datapath: Avoid using wrong metadata for recic action.

Recirc action needs to extract flow key from packet, it uses tun_info
from OVS_CB for setting tunnel meta data in flow key. But tun_info
can be overwritten by tunnel send action. This would result in wrong
flow key for the recirculation.
Following patch copies flow-key meta data from OVS_CB packet key
itself thus avoids this bug.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>