Fix exception cause in ptshell.py

Author: cool-RR

jupyter_console/ptshell.py

@@ -365,9 +365,9 @@ def init_kernel_info(self):
         while True:
             try:
                 reply = self.client.get_shell_msg(timeout=1)
-            except Empty:
+            except Empty as e:
                 if (time.time() - tic) > timeout:
-                    raise RuntimeError("Kernel didn't respond to kernel_info_request")
+                    raise RuntimeError("Kernel didn't respond to kernel_info_request") from e
             else:
                 if reply['parent_header'].get('msg_id') == msg_id:
                     self.kernel_info = reply['content']