Fix Cisco show bgp table parsing IPv4/6 mismatch

Fix Cisco parsing of show bgp ipv4/6 unicast sum when the opposite address
family peer is used. I.e. this:

sfc-c7200-gate.ai3.net#show bgp ipv4 unicast summary
<cut>
BGP activity 2403473/2329339 prefixes, 9040108/8863755 paths, scan interval 60 secs

Neighbor      V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
2001:D30:101:1::11
              4 4717 0     0       0      0   0    never   Active
202.249.24.4  4 4717 0     0       0      0   0    never   Active
202.249.24.36 4 4717 0     0       0      0   0    never   Active

Fixing issue https://github.com/tmshlvck/ulg/issues/10 .