datapath: Remove unnecessary flow variable.

Patch fixes following warning:
datapath/linux/flow_table.c:580:40: warning: symbol 'flow' shadows an earlier one
datapath/linux/flow_table.c:558:24: originally declared here

Reported-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
ofproto-dpif: Close race between processing packet_ins and checking seqno.

If a packet-in were to be queued, and the sequence number changed, after
grabbing the list of packet-ins, then the existing code could have gone to
sleep until something happened.  By grabbing the sequence number before
the list of packet-ins, we avoid this race.

Found by inspection.

Signed-off-by: Ben Pfaff <blp@nicira.com>