Fix passing user_ns to IPython.start_kernel()

IPython/kernel/zmq/kernelapp.py

@@ -393,6 +393,7 b' class IPKernelApp(BaseIPythonApplication, InteractiveShellApp):'
                                 stdin_socket=self.stdin_socket,
                                 log=self.log,
                                 profile_dir=self.profile_dir,
+                                user_ns=self.user_ns,
         )
         kernel.record_ports(self.ports)
         self.kernel = kernel