Define variables otherwise in case of delayed frontend instance creation

code will fail with :
"local variable 'user' referenced before assignment".
As callee is handling the possibility of delayed frontend and / or
instance creation this is perfectly fine.

erp5/util/testnode/SlapOSMasterCommunicator.py

@@ -382,6 +382,8 @@ class SlapOSTester(SlapOSMasterCommunicator):
   # In the future, this should allow customization so each project to be tested parses its own information,
   # probably in the test suite definition class
   def getInstanceUrlDict(self):
+    user = None
+    password = None
     frontend_url_list = []
     for instance in self.getInstanceUrlList():
       if "frontend-" in instance["title"]: