RFR 8191771: nashorn ant makefile uses javadoc -link which may fail

[Sundararajan Athijegannathan]

Please review.

Bug: https://bugs.openjdk.java.net/browse/JDK-8191771
Webrev: http://cr.openjdk.java.net/~sundar/8191771/webrev.00/

Thanks,
-Sundar