interpolate service_name in error message when service has no configuration options.

Signed-off-by: Dan Tenenbaum <dtenenba@fhcrc.org>

fig/project.py

@@ -67,7 +67,7 @@ class Project(object):
         dicts = []
         for service_name, service in list(config.items()):
             if not isinstance(service, dict):
-                raise ConfigurationError('Service "%s" doesn\'t have any configuration options. All top level keys in your fig.yml must map to a dictionary of configuration options.')
+                raise ConfigurationError('Service "%s" doesn\'t have any configuration options. All top level keys in your fig.yml must map to a dictionary of configuration options.' % service_name)
             service['name'] = service_name
             dicts.append(service)
         return cls.from_dicts(name, dicts, client)