Bug: fix typo (#137)

aztk/config.py

@@ -224,7 +224,7 @@ class ClusterConfig:
 
         if self.username is not None and self.wait is False:
             raise error.AztkError(
-                "You cannot create a user '{0}' if wait is set to true. By default, we create a user in the cluster.yaml file. Please either the configure your cluster.yaml file or set the parameter (--wait)".format(self.username))
+                "You cannot create a user '{0}' if wait is set to false. By default, we create a user in the cluster.yaml file. Please either the configure your cluster.yaml file or set the parameter (--wait)".format(self.username))
 
 
 class SshConfig: