bgpd: Fix output of interface based 'show bgp ..' commands

bgpd: Fix output of interface based 'show bgp ..' commands

When issuing a 'show ip bgp' command and the nexthop is
a interface, if the interface name was greater than 7 characters
we would arbitrarily start a new-line and setup the next
line to start at the wrong spot.

Modify the interface field to allow 16 characters than 7( to
match v6 display ), and if the interface name is greater than
16 characters properly setup the next line for display

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>