scalability_test: fix return in init test suite method

scalability_test/__init__.py

@@ -30,7 +30,7 @@ class WendelinERP5_scalability():
     metrics_url = "http://%s:%s@%s/erp5" % (instance_information_dict['user'],
                                     instance_information_dict['password'],
                                     instance_information_dict['zope-address'])
-    metrics_url += "/ERP5Site_getScalabilityTestMetric"
+    return metrics_url + "/ERP5Site_getScalabilityTestMetric"
 
   def getBootstrapScalabilityTestUrl(self, count=0, instance_information_dict, **kw):
     bootstrap_url = "http://%s:%s@%s/erp5" % (instance_information_dict['user'],