RFR 8194922: jlink --exclude-resources should never exclude module-info.class

[Sundararajan Athijegannathan]

Please review.

Webrev: http://cr.openjdk.java.net/~sundar/8194922/webrev.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8194922

Thanks
-Sundar