[Contesting] Check if QSOTable is initialised

This fixes the javascript error reported in #981 not sure if it solves all the issues though

application/views/interface_assets/footer.php

@@ -1854,7 +1854,7 @@ function deleteQsl(id) {
                                 '<td>'+ receivedexchange + '</td>' +
                                 '</tr>');
                         });
-
+                        if (!$.fn.DataTable.isDataTable('.qsotable')) {
                             $('.qsotable').DataTable({
                                 "pageLength": 25,
                                 responsive: false,
@@ -1865,6 +1865,7 @@ function deleteQsl(id) {
                                 "order": [[ 0, "desc" ]]
                             });
                         }
+                    }
                 });
             }
         }