diff --git a/common/config.py b/common/config.py
index 7fc6a40..f07ee86 100644
--- a/common/config.py
+++ b/common/config.py
@@ -66,8 +66,8 @@
                default='private',
                help="Visible fixed network name "),
     cfg.StrOpt('boot_config_env',
-               default='heat_integrationtests/scenario/templates'
-                       '/boot_config_none_env.yaml',
+               default=('heat_integrationtests/scenario/templates'
+                        '/boot_config_none_env.yaml'),
                help="Path to environment file which defines the "
                     "resource type Heat::InstallConfigAgent. Needs to "
                     "be appropriate for the image_ref."),