Avoid show management_interface address failed if no default gateway

Signed-off-by: irene_pan irene_pan@edge-core.com

Author: irene-pan1202

show/main.py

@@ -528,7 +528,10 @@ def address ():
     mgmt_ip_data = config_db.get_table('MGMT_INTERFACE')
     for key in natsorted(list(mgmt_ip_data.keys())):
         click.echo("Management IP address = {0}".format(key[1]))
-        click.echo("Management Network Default Gateway = {0}".format(mgmt_ip_data[key]['gwaddr']))
+        if mgmt_ip_data[key].get('gwaddr') is not None:
+            click.echo("Management Network Default Gateway = {0}".format(mgmt_ip_data[key]['gwaddr']))
+        else:
+            click.echo("Management Network Default Gateway = ")
 
 #
 # 'snmpagentaddress' group ("show snmpagentaddress ...")