multiple fixes nxos (#32903)

Signed-off-by: Trishna Guha <trishnaguha17@gmail.com>

lib/ansible/module_utils/nxos.py

@@ -169,7 +169,7 @@ class Cli:
                 except ValueError:
                     out = to_text(out).strip()
 
-            if item['output'] == 'json' and out != 'ok' and isinstance(out, string_types):
+            if item['output'] == 'json' and out != '' and isinstance(out, string_types):
                 self._module.fail_json(msg='failed to retrieve output of %s in json format' % item['command'])
 
             responses.append(out)

lib/ansible/modules/network/nxos/nxos_interface.py

@@ -488,6 +488,9 @@ def get_interface_config_commands(interface, intf, existing):
     if mtu != 'None':
         commands.append('mtu {0}'.format(mtu))
 
+    if 'mtu None' in commands:
+        commands.pop()
+
     admin_state = interface.get('admin_state')
     if admin_state:
         command = get_admin_state(interface, intf, admin_state)