Request for integrating #235471 - AssertionError: cdnjs-cdnjs-754b27a/ajax/libs/package.json

Bug link:
https://netbeans.org/bugzilla/show_bug.cgi?id=235471

Description of the bug:
NetBeans can update bundled list of JavaScript libraries. Unfortunately,
the content of the ZIP archive we use does not have any format specified
so we must be very defensive. This fix improves the current behaviour.

Impact assessment:
This impacts all NetBeans users who try to update their JS libraries.

Risk assessment:
IMHO there is no risk since the assertion was simply replaced by a
proper check.

Fix:
http://hg.netbeans.org/web-main/rev/a746f00e37da

The fix was written by tmysik, reviewed by dkonecny and verifed by vriha.

Thanks for the review,
Tomas