bgpd: adjust display format

[anlancs]

Just adjust display format for show bgp ipv6 unicast, add two white spaces.

Before:

     Network          Next Hop            Metric LocPrf Weight Path
 *>i 3001::/64        fe80::2e53:4aff:fe30:820
                                             0    100      0 i

After:

     Network          Next Hop            Metric LocPrf Weight Path
 *>i 3001::/64        fe80::2e53:4aff:fe30:820
                                               0    100      0 i

[ton31337]

Could you check if it's not broken for other AFIs/SAFIs, including the wide option? (Not saying this commit breaks something, but since you are here, it's worth asking this)

[anlancs]

@ton31337
Yes, i have tested ipv6/ipv4, and wide for them. ipv4 is short string, so it can't enter this scene which requires new line.
But the left cases are strange to me, so i didn't test them....
As to the code, the left cases should have the same procedure.