RFR: JDK-8244758,: DMG bundler ignores --install-dir option.

[Andy Herrick]

Please review jpackage fix for issue [1] at [2].

The change allows the specified --install-dir (instead of always 
/Applications) to be suggested for drag target of a DMG image.

[1] - https://bugs.openjdk.java.net/browse/JDK-8244758

[2] - http://cr.openjdk.java.net/~herrick/8244758

/Andy