testnode: ScalabilityTestRunner: Use json correct format

erp5/util/testnode/ScalabilityTestRunner.py

@@ -121,6 +121,7 @@ class ScalabilityTestRunner():
       config = self._generateInstanceXML(software_configuration,
                                     test_result, test_suite)
       self.log("testnode, request : %s", instance_title)
+      config = json.dumps(config)
       self.slapos_controler.request(instance_title, software_path,
                              "scalability", {"_" : config},
                              self.launcher_nodes_computer_guid[0])
@@ -197,6 +198,7 @@ late a SlapOS (positive) answer." %(str(os.getpid()),str(os.getpid()),))
     """
     config = self._generateInstanceXML(software_configuration,
                                   test_result, test_suite)
+    config = json.dumps(config)
     self.log("testnode, updateInstanceXML : %s", instance_title)
     self.slapos_controler.updateInstanceXML(instance_title, {"_" : config})
     return {'status_code' : 0}