Fix prefixes in syncgroup test.

Change-Id: I5cafd69031be482be3204974ba03e4fd506047de
diff --git a/test/integration/test-syncgroup.js b/test/integration/test-syncgroup.js
index 8479f59..3b5903b 100644
--- a/test/integration/test-syncgroup.js
+++ b/test/integration/test-syncgroup.js
@@ -262,12 +262,12 @@
 
   var newSpec = new nosql.SyncGroupSpec({
     description: 'new spec',
-    prefixes: ['a']
+    prefixes: prefixes
   });
 
   var newSpec2 = new nosql.SyncGroupSpec({
     description: 'another new spec',
-    prefixes: ['b']
+    prefixes: prefixes
   });
 
   setupSyncGroup(t, perms, prefixes, function(err, o) {