fix a bug with errors handling

src/jflow/workflow.py

@@ -596,6 +596,7 @@ class Workflow(threading.Thread):
         if odict.has_key('external_components') :
             del odict['external_components']
         if odict.has_key('stderrfh') :
+            self.stderrfh.close()
             del odict['stderrfh']
         return odict