- track packets dropped in the linux specific layer

- avoid double counting packets that hit an encap nexthop and has to undergo
GRO processing by having separate counters for GRO and Encaps (can be seen
through vrfstats)
- add a new vif to count packets that were sent for GRO and received post GRO
processing. Also track GRO errors in those stats.
- fix the dump loop in vrfstats utility ('more' has to be marked false after
the last record is seen)