ofproto-dpif-xlate: After thawing, retrieve tunnel table from thawed xbridge

ofproto-dpif-xlate: After thawing, retrieve tunnel table from thawed xbridge

In xlate_actions in ofproto-dpif-xlate.c, after thawing from frozen state,
it currently retrieves the tunnel metadata table from the original xbridge.
It should retrieve the tunnel metadata table from the thawed xbridge.

In OVN, this manifested as missing geneve option fields when receiving a
packet from localnet to br-int, then freezing (e.g. for NAT on a gateway
router or for distributed NAT), then attempting to send out a tunnel.

Signed-off-by: Mickey Spiegel <mickeys.dev@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>