fix changes test to make it wokr on all browsers
diff --git a/script/test/changes.js b/script/test/changes.js
index 7c0af0f..91fde7e 100644
--- a/script/test/changes.js
+++ b/script/test/changes.js
@@ -140,7 +140,7 @@
     xhr.abort();
 
     // test Server Sent Event (eventsource)
-    if (window.EventSource) {
+    if (!!window.EventSource) {
       var source = new EventSource(
               "/test_suite_db/_changes?feed=eventsource");
       var results = [];