GUI: only warn about errors while we are updating manifest

dream/platform/src/dream/index.js

@@ -15,7 +15,11 @@
   // Prompt user to reload after manifest update.
   // from http://www.html5rocks.com/en/tutorials/appcache/beginner/#toc-updating-cache
   window.addEventListener('load', function() {
+    var updating = false;
     if (window.applicationCache) {
+      window.applicationCache.addEventListener('downloading', function() {
+        updating = true;
+      }, false);
       window.applicationCache.addEventListener('updateready', function() {
           if (window.applicationCache.status === window.applicationCache.UPDATEREADY) {
             // Browser downloaded a new app cache.
@@ -27,7 +31,11 @@
           }
       }, false);
       window.applicationCache.addEventListener('error', function() {
-        alert("Fatal error while updating, retrying"); window.location.reload();}, false );
+        if (updating){
+         alert("Fatal error while updating, retrying");
+         window.location.reload();
+        }
+      }, false );
     }
   }, false);