NAT service broken when BgpVpn is associated to external network

NAT service originally works when external network is created and then associated with bgpvpn. Recent changes in the design wherein transparentVpn is supported for NAT has broken the regular bgpvpn case.

In the below NAT pipeline, after SNAT translated entry in table 46, metadata match not happening in table 47. This needs to be fixed.

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stack@os-ctrl:~/devstack$ sudo ovs-ofctl dump-flows br-int -O OpenFlow13 | grep table=46
cookie=0x8122171, duration=6.580s, table=46, n_packets=6, n_bytes=444, idle_timeout=300, send_flow_rem priority=10,tcp,metadata=0x222e2/0xfffffffe,nw_src=10.1.0.2,tp_src=31333 actions=set_field:172.16.0.2->ip_src,set_field:49152->tcp_src,write_metadata:0x222e8/0xfffffffe,goto_table:47
cookie=0x812117a, duration=1678.918s, table=46, n_packets=2, n_bytes=148, priority=5,ip,metadata=0x222e2/0xfffffffe actions=CONTROLLER:65535,write_metadata:0x222e2/0xfffffffe
stack@os-ctrl:~/devstack$ sudo ovs-ofctl dump-flows br-int -O OpenFlow13 | grep table=47
cookie=0x8000006, duration=1706.889s, table=47, n_packets=0, n_bytes=0, priority=5,ip,metadata=0x222e2/0xfffffffe actions=resubmit(,21)
cookie=0x8000006, duration=1706.755s, table=47, n_packets=0, n_bytes=0, priority=5,ip,metadata=0x222e0/0xfffffffe actions=resubmit(,21)

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