bgpd: display multipath status in "show ip bgp"

bgpd: display multipath status in "show ip bgp"

The output of "show ip bg" does not show whether and which routes are
installed as multipath routes along the best route:

BGP table version is 0, local router ID is 10.10.100.209
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*>i1.0.0.0/24       10.10.100.1              1    111      0 15169 i
* i                 10.10.100.2              1    111      0 15169 i
* i                 10.10.100.3              1    111      0 65100 15169 i

This patch adds a new status code that is showing exactly which routes
are used as multipath:

BGP table version is 0, local router ID is 10.10.100.209
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
              i internal, r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*>i1.0.0.0/24       10.10.100.1              1    111      0 15169 i
*=i                 10.10.100.2              1    111      0 15169 i
* i                 10.10.100.3              1    111      0 65100 15169 i

The inconsistency in the status code legend ("i - internal" vs. "i internal")
inherent from old IOS was fixed. It had to be touched anyways.

Signed-off-by: Boian Bonev <bbonev at ipacct.com>
[DL: rewrap long line, clean whitespace in same chunk]
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>