Fix nilpointer if CALICO_NETWORKING_BACKEND=none

There is a nil pointer in the configureASNumber function if the networking backend is none (i.e. policy-only mode)

Signed-off-by: Tobias Giese <tobias.giese@mercedes-benz.com>

node/pkg/lifecycle/startup/startup.go

@@ -439,7 +439,6 @@ func waitForConnection(ctx context.Context, c client.Interface) {
 		// is working.  Getting a specific Node is a good option, even
 		// if the Node does not exist.
 		_, err := c.Nodes().Get(ctx, "foo", options.GetOptions{})
-
 		// We only care about a couple of error cases, all others would
 		// suggest the datastore is accessible.
 		if err != nil {
@@ -675,7 +674,6 @@ func evaluateENVBool(envVar string, defaultValue bool) bool {
 	if isSet {
 
 		switch strings.ToLower(envValue) {
-
 		case "false", "0", "no", "n", "f":
 			log.Infof("%s is %t through environment variable", envVar, false)
 			return false
@@ -691,6 +689,12 @@ func evaluateENVBool(envVar string, defaultValue bool) bool {
 // in the environment, or is a no-op if not specified.
 // Returns true if the node object needs to be updated.
 func configureASNumber(node *libapi.Node) bool {
+	// If Calico is running in policy only mode we don't need to write BGP related
+	// details to the Node.
+	if os.Getenv("CALICO_NETWORKING_BACKEND") == "none" {
+		return false
+	}
+
 	// Extract the AS number from the environment
 	asStr := os.Getenv("AS")
 	if asStr != "" {
@@ -861,7 +865,6 @@ func configureIPPools(ctx context.Context, client client.Interface, kubeadmConfi
 
 		createIPPool(ctx, client, ipv6Cidr, DEFAULT_IPV6_POOL_NAME, string(api.IPIPModeNever), ipv6VXLANModeEnvVar, outgoingNATEnabled, ipv6BlockSize, ipv6NodeSelector, bgpExportDisabled)
 	}
-
 }
 
 // createIPPool creates an IP pool using the specified CIDR.  This