bgpd: Filtering received EVPN routes based on VNI does not work

bgpd: Filtering received EVPN routes based on VNI does not work

Issue1: When "neighbor X.X.X.X route-map RM-VNI-FILTER in" is configured under evpn address-family,
all the received routes are dropped regardless of whether the route has a matching vni or not.

Issue2: Routes with 2 labels are not filtered correctly

Issue3: Interpreting the label based on tunnel type, vxlan was not done correctly.
Vxlan label has 24 bits, whereas, MPLS label is 20 bits long

Fix1: The handler bgp_update() that services the received route ignored the route's label while deciding whether to filter it or not. As part of the fix, the handler now uses the label info to make the decision about whether to filter the route or not.

Fix2: route_match_vni() now tries to match both the labels within the route, not just the one.

Signed-off-by: Lakshman Krishnamoorthy <lkrishnamoor@vmware.com>