lint fix

Author: Mikolaj Umanski

src/azure-cli/azure/cli/command_modules/acs/_validators.py

@@ -835,4 +835,3 @@ def validate_message_of_the_day(namespace):
         if namespace.os_type is not None and namespace.os_type != "Linux":
             raise ArgumentUsageError(
                 '--message-of-the-day can only be set for linux nodepools')
-