ldpd: improve ordering of interfaces on user output

ldpd: improve ordering of interfaces on user output

Before:

debian# show mpls ldp interface
AF   Interface   State  Uptime   Hello Timers  ac
ipv4 rt0-eth0    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth1    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth10   ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth11   ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth2    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth3    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth4    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth5    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth6    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth7    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth8    ACTIVE 00:00:05 5/15           1
ipv4 rt0-eth9    ACTIVE 00:00:05 5/15           1

After:

debian# show mpls ldp interface
AF   Interface   State  Uptime   Hello Timers  ac
ipv4 rt0-eth0    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth1    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth2    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth3    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth4    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth5    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth6    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth7    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth8    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth9    ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth10   ACTIVE 00:00:14 5/15           1
ipv4 rt0-eth11   ACTIVE 00:00:14 5/15           1

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>