for ovs-appctl bridge/dump-flows, don't show "priority" twice

before the change:

duration=2110s, priority=0, n_packets=3151646, n_bytes=3104180388, \
priority=0,actions=CONTROLLER:65535
table_id=254, duration=2136s, priority=0, n_packets=0, n_bytes=0, \
priority=0,reg0=0x3,actions=drop
table_id=254, duration=2136s, priority=0, n_packets=0, n_bytes=0, \
priority=0,reg0=0x1,actions=controller(reason=no_match)
table_id=254, duration=2136s, priority=0, n_packets=0, n_bytes=0, \
priority=0,reg0=0x2,actions=drop

after the change:

duration=2924s, n_packets=5316116, n_bytes=5260045454, \
priority=0,actions=CONTROLLER:65535
table_id=254, duration=2924s, n_packets=0, n_bytes=0, \
priority=0,reg0=0x3,actions=drop
table_id=254, duration=2924s, n_packets=0, n_bytes=0, \
priority=0,reg0=0x1,actions=controller(reason=no_match)
table_id=254, duration=2924s, n_packets=0, n_bytes=0, \
priority=0,reg0=0x2,actions=drop

(i wrapped long lines by hand)