ndev.l2_ports.catalog returns nil on MX80

[PeiwenChen]

hi,
The ndev.l2_ports.catalog returns nil on MX80.
I believe its because this RPC command returns nil:
https://github.com/Juniper/ruby-junos-ez-stdlib/blob/master/lib/junos-ez/l2_ports/vlan.rb#L323

Can you fix it?

peiwen@chi-cr-01> show ethernet-switching interface    

peiwen@chi-cr-01> 
[0] 0:bash- 1:ssh*
peiwen@chi-cr-01> show version 
Hostname: chi-cr-01
Model: mx80
JUNOS Base OS boot [12.3R8.7]
JUNOS Base OS Software Suite [12.3R8.7]
JUNOS Kernel Software Suite [12.3R8.7]
JUNOS Crypto Software Suite [12.3R8.7]
JUNOS Packet Forwarding Engine Support (MX80) [12.3R8.7]
JUNOS Online Documentation [12.3R8.7]
JUNOS Routing Software Suite [12.3R8.7]