[9] Review request: JDK-8134725: Gradle openZip task does not support JDK9 layout

[Kevin Rushforth]

Hi David,

Please review this simple fix to the build logic for the openZip task.

https://bugs.openjdk.java.net/browse/JDK-8134725
http://cr.openjdk.java.net/~kcr/8134725/webrev.00/

-- Kevin