RFR: JDK-8233591: Reorder jpackage help text to focus on package

[Andy Herrick]

Please review the revised jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

This fix (webrev.02) was revised after feedback from webrev.01.

[1] https://bugs.openjdk.java.net/browse/JDK-8233591

[2] http://cr.openjdk.java.net/~herrick/8233591/webrev.02/

/Andy