Coordinator concurrency control can't be more than 12

<coordinator-app name="xxx" frequency="2,7,12,17,22,27,32,37,42,47,52,57 * * * *" start="${start_date}" end="${end_date}"
    timezone="${data_timezone}" xmlns="uri:oozie:coordinator:0.4" xmlns:sla="uri:oozie:sla:0.2">
    <controls>
        <concurrency>24</concurrency>
        <execution>FIFO</execution>
        <throttle>24</throttle>
    </controls>
    ...
</coordinator-app>