Pass websocket Close frame into ConnectionClosed

Fixes #989

Author: cderici

juju/client/connection.py

@@ -470,7 +470,9 @@ async def close(self, to_reconnect=False):
 
     async def _recv(self, request_id):
         if not self.is_open:
-            raise websockets.exceptions.ConnectionClosed(0, 'websocket closed')
+            raise websockets.exceptions.ConnectionClosed(
+                websockets.frames.Close(websockets.frames.CloseCode.NORMAL_CLOSURE,
+                                        'websocket closed'))
         try:
             return await self.messages.get(request_id)
         except GeneratorExit:
@@ -641,7 +643,8 @@ async def rpc(self, msg, encoder=None):
             if self.monitor.status == Monitor.DISCONNECTED:
                 # closed cleanly; shouldn't try to reconnect
                 raise websockets.exceptions.ConnectionClosed(
-                    0, 'websocket closed')
+                    websockets.frames.Close(websockets.frames.CloseCode.NORMAL_CLOSURE,
+                                            'websocket closed'))
             try:
                 await self._ws.send(outgoing)
                 break