Merge pull request jupyter-server#444 from afshin/unbound-local-error

Fix for UnboundLocalError in shutdown

Author: blink1073

jupyter_server/utils.py

@@ -224,5 +224,7 @@ def wrapped():
             if str(e) == 'This event loop is already running':
                 # just return a Future, hoping that it will be awaited
                 result = asyncio.ensure_future(maybe_async)
+            else:
+                raise e
         return result
-    return wrapped()
+    return wrapped()