logging fix

src/python/dm/daq_web_service/service/experimentSessionController.py

@@ -84,7 +84,7 @@ class ExperimentSessionController(DmSessionController):
             raise InvalidRequest('Missing data directory.')
         dataDirectory = Encoder.decode(dataDirectory)
         if not dataDirectory.startswith('/') and not dataDirectory.count('://'):
-            raise InvalidRequest('Data directory must be an absolute path.')
+            raise InvalidRequest('Data directory must be an absolute path: %s' % dataDirectory)
 
         daqInfo = {}
         encodedDaqInfo = kwargs.get('daqInfo')