clones.js: minor corrections

browser/js/clone.js

@@ -1168,7 +1168,7 @@ Clone.prototype = {
             }
         }
         if (typeof this.seg.junction != 'undefined' &&
-            this.seg.junction.aa != "undefined") {
+            typeof this.seg.junction.aa != "undefined") {
             html += row_1("junction (AA seq)", this.getSegAASequence('junction'))
         }