bgpd: dynamically grow 'show ip bgp summ' Neighbor column width

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>
Reviewed-by:   Donald Sharp <sharpd@cumulusnetworks.com>

Now that we display hostnames in 'show ip bgp summary' it is really easy
to have the first column be greater than 16 characters which causes a
line wrap. The line wrap makes the output difficult to read.

Before
======
superm-redxp-05# show ip bgp summ
BGP router identifier 6.0.0.11, local AS number 65001 vrf-id 0
BGP table version 56
RIB entries 19, using 2280 bytes of memory
Peers 2, using 41 KiB of memory
Peer groups 1, using 64 bytes of memory

Neighbor        V         AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd
leaf-11-really-long-name(swp1)
                4      65101     307     322        0    0    0 00:14:15 10
leaf-12(swp2)   4      65101     105     121        0    0    0 00:14:14 Idle (Admin)

Total number of neighbors 2
superm-redxp-05#

After
=====
superm-redxp-05# show ip bgp summ
BGP router identifier 6.0.0.11, local AS number 65001 vrf-id 0
BGP table version 10
RIB entries 19, using 2280 bytes of memory
Peers 2, using 41 KiB of memory
Peer groups 1, using 64 bytes of memory

Neighbor                       V         AS MsgRcvd MsgSent   TblVer InQ OutQ  Up/Down State/PfxRcd
leaf-11-really-long-name(swp1) 4      65101      11      12        0   0    0 00:00:08           10
swp2                           4          0       0       0        0   0    0    never Idle (Admin)

Total number of neighbors 2
superm-redxp-05#
superm-redxp-05#

0 files changed, 0 insertions, 0 deletions