tests: update authentication test fixture

The HWOBJ.set_property() method has been removed. Manipulate the
lims HWOBJ's configuration using it's 'config' attribute.

Author: elmjag

Diff for: test/test_authn.py

@@ -51,7 +51,7 @@ def server(request, login_type):
 
     hw_repo = mxcubecore.HardwareRepository.get_hardware_repository()
     lims = hw_repo.get_hardware_object("lims")
-    lims.set_property("loginType", login_type)
+    lims.config.loginType = login_type
 
     yield server_