[AC-2039] Bluring the SearchBar should not disable Cancel button

   var win = Ti.UI.createWindow({});
   var SearchBar = Ti.UI.createSearchBar({
		top: 0,
		showCancel: true,
		height: '42dp',
	});
   win.add(SearchBar);

   win.open();
   SearchBar.blur();

In this instance the keyboard disappears, but the Cancel button becomes inactive. As an example of why this is incorrect behaviour see the default Mail app on an iPad. Perform a search in mail. Lower the keyboard. Cancel remains active and the user can dismiss search.