remove now useless append check in user_mod

library/user

@@ -173,10 +173,6 @@ def user_mod(user, **kwargs):
             if kwargs[key] is not None and info[1] != kwargs[key]:
                 cmd.append('-p')
                 cmd.append(kwargs[key])
-        elif key == 'append':
-            if kwargs[key] is not None and kwargs[key] == 'yes':
-                if 'groups' in kwargs and kwargs['groups'] is not None:
-                    cmd.append('-a')
     # skip if no changes to be made
     if len(cmd) == 1:
         return False