Merge pull request #4034 from Carreau/adaptation-log

When adapting also log the version jupyter_client is expecting.

notebook/services/kernels/handlers.py

@@ -187,7 +187,7 @@ class ZMQChannelsHandler(AuthenticatedZMQStreamHandler):
         protocol_version = info.get('protocol_version', client_protocol_version)
         if protocol_version != client_protocol_version:
             self.session.adapt_version = int(protocol_version.split('.')[0])
-            self.log.info("Adapting to protocol v%s for kernel %s", protocol_version, self.kernel_id)
+            self.log.info("Adapting from protocol version {protocol_version} (kernel {kernel_id}) to {client_protocol_version} (client).".format(protocol_version=protocol_version, kernel_id=self.kernel_id, client_protocol_version=client_protocol_version))
         if not self._kernel_info_future.done():
             self._kernel_info_future.set_result(info)