Position drop fix

The variable that was finding the element for the new position was actually finding the new position for every rack on the screen and it was defaulting to the first rack on the screen's position.  Changed the selector to find the correct one. close opendcim#710

scripts/common.js

@@ -1212,7 +1212,7 @@ function initdrag(){
 				// U above device + height of device in U + X rows for the header
 				var diff=Math.round(ui.position.top/21) + Math.ceil(this.offsetHeight/21) + getElementIndex(topu[0]);
 				var newposition=parseInt($(this.parentElement.parentElement.parentElement.parentElement).find('tr:nth-child('+diff+') td:first-child').text());
-				var newu=$('tr#pos' + newposition);
+				var newu=topu.parents('.cabinet').find('tr#pos' + newposition);
 				var device=this;
 				device.style.left=ui.position.left+'px';
 				device.style.top=ui.position.top+'px';