[QSO edit] Check grid length to stop distance/bearing call when grid is removed

assets/js/sections/common.js

@@ -139,10 +139,12 @@ function qso_edit(id) {
                     });
 
                     $('#locator').change(function(){
+                        if ($(this).val().length >= 4) {
                             $('#locator_info').load("logbook/searchbearing/" + $(this).val() + "/" + $('#stationProfile').val()).fadeIn("slow");
                             $.get('logbook/searchdistance/' + $(this).val() + "/" + $('#stationProfile').val(), function(result) {
                                 document.getElementById("distance").value = result;
                             });
+                        }
                     });
 
                     $('#sota_ref_edit').selectize({