use retry_json nxos_banner (#44376)

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

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

@@ -98,14 +98,7 @@ def execute_show_command(module, command):
         'command': command,
         'output': format,
     }]
-    output = run_commands(module, cmds, False)
-    if len(output) == 0 or len(output[0]) == 0:
-        # If we get here the platform does not
-        # support structured output.  Resend as
-        # text.
-        cmds[0]['output'] = 'text'
-        output = run_commands(module, cmds, False)
-
+    output = run_commands(module, cmds, check_rc='retry_json')
     return output
 
 
@@ -130,7 +123,7 @@ def map_config_to_obj(module):
     output = execute_show_command(module, command)[0]
 
     if "Invalid command" in output:
-        module.fail_json(msg="banner: exec may not be supported on this platform.  Possible values are : exec | motd")
+        module.fail_json(msg="banner: %s may not be supported on this platform.  Possible values are : exec | motd" % module.params['banner'])
 
     if isinstance(output, dict):
         output = list(output.values())