RFR(XS): 8055243: Make jdk8u40 the default release

[Tim Bell]

Hi Mikael:

> Please review this small change which updates the default jprt release 
> for jdk8u/jdk8u-dev to jdk8u40.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8055243
> Webrev: 
> http://cr.openjdk.java.net/~mikael/webrevs/8055243/webrev.00/webrev/
>

Looks good to me.

Tim