item: Reorder columns in tracking listbox

Having the "Origin" before the "Site" makes it more readable, it
reads like:
Source Destination
Source Destination

which is easier to understand than
Destination Source
Destination Source

bt5/erp5_item/SkinTemplateItem/portal_skins/erp5_item/Item_viewTrackingList/listbox.xml

@@ -90,14 +90,14 @@
                           <string>date</string>
                           <string>Date</string>
                         </tuple>
-                        <tuple>
-                          <string>node_title</string>
-                          <string>Site or Warehouse</string>
-                        </tuple>
                         <tuple>
                           <string>source_title</string>
                           <string>Origin</string>
                         </tuple>
+                        <tuple>
+                          <string>node_title</string>
+                          <string>Site or Warehouse</string>
+                        </tuple>
                         <tuple>
                           <string>section_title</string>
                           <string>Organisation</string>