fix: update correct subdept dropdown when dept value changes

previously the jquery selector was always finding / affecting the
"first" subdept dropdown in the table.  but it should find/affect the
"current row" subdept dropdown instead

Refs: #1225

fannie/item/productList.js

@@ -33,12 +33,12 @@ var productList = (function($) {
  var departmentChanged = function(event) {
  var deptSelect = event.target;
  var dept = $(deptSelect).val();
+ var subdepts = subdeptMap[dept];
 
- // update available subdepts
- var obj = subdeptMap[dept];
- var td = $('.td_subdept');
- td.find('select')[0].remove();
- drawKeyValSelect(td.parents('tr:first'), 'td_subdept', 'in_subdept', obj);
+ // replace dropdown to update available subdepts
+ var tr = $(deptSelect).parents('tr:first');
+ tr.find('.td_subdept select')[0].remove();
+ drawKeyValSelect(tr, 'td_subdept', 'in_subdept', subdepts);
  };
 
  var drawTupleSelect = function(elem, cell, field, obj) {