When testing fix for NETVIRT-1249 we uncovered another race condition where routerId was -1 for default snat flow.

Table:21, Host:127745018911474, DpnId:127745018911474/0x742ef4795af2, FlowId:DefaultFibRouteForSNATSNAT.127745018911474.21.​​-1,VpnId:8388607/0xfffffe,Reason:VpnInstance for VpnId not found
('Flow: ', '{"barrier": false, "flow-name": "DefaultFibRouteForSNATSNAT.127745018911474.21.-1", "idle-timeout": 0, "installHw": true, "priority": 10, "strict": false, "table_id": 21, "id": "DefaultFibRouteForSNATSNAT.127745018911474.21.-1", "cookie": "0x8000006", "hard-timeout": 0, "match": {"ethernet-match": {"ethernet-type": {"type": 2048}}, "metadata": {"metadata-mask": "0xfffffe", "metadata": "0xfffffe"}}, "instructions": {"instruction": [{"go-to-table":

, "order": 0}]}}')

This leads to failure in some of the tempest FIP test cases.