Bug8484: Non-NAPT Group action is drop for router associated with BGP-VPN

Bug8484: Non-NAPT Group action is drop for router associated with BGP-VPN

Problem Description:
======================
Non-NAPT to NAPT VM Traffic is getting dropped at Non-NAPT Group level
when router is being associated with private BGP-VPN.

Solution:
===========
When ever Vxlan tunnel got "down" followed by "up" event between Non-NAPT to
Napt Switch happened, Non-Napt group got re-created through tunnel
interface state listener. In this use case is not been properly having the
code logic for if the router with private bgp-vpn configured.

Added the proper code for creating tunnel bucket information for Non-NAPT
groups got re-created during tunnel state changed.

Change-Id: I509eeda9041d5e1b170e45554b3d9f661e6091fd
Signed-off-by: karthikeyan <karthikeyan.k@altencalsoftlabs.com>