Update source/DatePicker.js
Update source/DatePicker.js

Fix problem where disabledChanged didn't use $ to find items in the hash, reported on forums at http://forums.enyojs.com/discussion/925/bug-in-enyo-2-1-datepicker-js

Enyo-DCO-1.0-Signed-Off-By: Ben Combee (ben.combee@palm.com)
enyojs/onyx,onecrayon/onyx,enyojs/onyx,mcanthony/onyx,mcanthony/onyx,onecrayon/onyx