Discovery picks up VRFs that do not have RDs assigned

The discovery poller picks up VRFs that do not have RDs assigned to them, breaking some UI functions that rely on linking RDs to VRFs. Easiest workaround would be to ignore VRFs that have blank RDs. This only affects MPLS-L3VPN-STD-MIB – MPLS-VPN-MIB will not enumerate VRFs that have no RD set.

This issue mostly affects Cisco IOS-XR, as it will pick up the internal-only VRFs **eint and **nvSatellite

snmpwalk -v 2c -c public router1 MPLS-VPN-MIB::mplsVpnVrfRouteDistinguisher
MPLS-VPN-MIB::mplsVpnVrfRouteDistinguisher = No Such Object available on this agent at this OID

snmpwalk -v 2c -c public router1 MPLS-L3VPN-STD-MIB::mplsL3VpnVrfRD
MPLS-L3VPN-STD-MIB::mplsL3VpnVrfRD."**eint" = ""
MPLS-L3VPN-STD-MIB::mplsL3VpnVrfRD."**nVSatellite" = ""