Backport PR #2170: Fix tab completion with IPython.embed_kernel().

Closes  #2162.

IPython/core/interactiveshell.py

@@ -1808,7 +1808,6 b' class InteractiveShell(SingletonConfigurable):'
             self.readline_no_record = no_op_context
             self.set_readline_completer = no_op
             self.set_custom_completer = no_op
-            self.set_completer_frame = no_op
             if self.readline_use:
                 warn('Readline services not available or not loaded.')
         else:

IPython/zmq/ipkernel.py

@@ -908,6 +908,7 b' def embed_kernel(module=None, local_ns=None, **kwargs):'
     
     app.kernel.user_module = module
     app.kernel.user_ns = local_ns
+    app.shell.set_completer_frame()
     app.start()
 
 def main():