[10] RFR JDK-8089962:[FXDnD]: in removeDropTarget the isDropTargetListenerInstalled field isn't reset

[Prasanta Sadhukhan]

Hi All,

Please review a fix
http://cr.openjdk.java.net/~psadhukhan/fx/8089962/webrev.00/
for issue
https://bugs.openjdk.java.net/browse/JDK-8089962

More info in JBS.

Regards
Prasanta