Fix javascript strict warning for assignment to undeclared variable. No bug.

git-svn-id: svn://10.0.0.236/trunk@221539 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/calendar/base/content/preferences/timezones.js

@@ -41,8 +41,8 @@
 var gTimezonesPane = {
     init: function () {
         var tzMenuList = document.getElementById("calendar.timezone.menulist");
-        prefValue = document.getElementById("calendar.timezone.local").value;
-        
+        var prefValue = document.getElementById("calendar.timezone.local").value;
+
         if (!prefValue) {
             prefValue = calendarDefaultTimezone();
             tzMenuList.value = prefValue;