when router is deleted return success for static route deletion (#4266)

Signed-off-by: oilbeater <liumengxinfly@gmail.com>

pkg/ovs/ovn-nb-logical_router_route.go

@@ -136,12 +136,17 @@ func (c *OVNNbClient) UpdateLogicalRouterStaticRoute(route *ovnnb.LogicalRouterS
 	return nil
 }
 
-// DeleteLogicalRouterStaticRoute add a logical router static route
+// DeleteLogicalRouterStaticRoute delete a logical router static route
 func (c *OVNNbClient) DeleteLogicalRouterStaticRoute(lrName string, routeTable, policy *string, ipPrefix, nexthop string) error {
 	if policy == nil || len(*policy) == 0 {
 		policy = ptr.To(ovnnb.LogicalRouterStaticRoutePolicyDstIP)
 	}
 
+	lr, err := c.GetLogicalRouter(lrName, true)
+	if lr == nil && err == nil {
+		return nil
+	}
+
 	routes, err := c.ListLogicalRouterStaticRoutes(lrName, routeTable, policy, ipPrefix, nil)
 	if err != nil {
 		klog.Error(err)