checks commit comment to make sure it doesn't exceed 60 characters (#5155)

The comment argument can be at most 60 characters per the IOS XR command
line.  If a comment is > 60 characters, the module will now gracefully error
and return a well formed message.

fixes 5146

network/iosxr/iosxr_config.py

@@ -194,6 +194,9 @@ DEFAULT_COMMIT_COMMENT = 'configured by iosxr_config'
 
 
 def check_args(module, warnings):
+    if module.params['comment']:
+        if len(module.params['comment']) > 60:
+            module.fail_json(msg='comment argument cannot be more than 60 characters')
     if module.params['force']:
         warnings.append('The force argument is deprecated, please use '
                         'match=none instead.  This argument will be '