Gyuho Lee d922069713 grpcproxy: fix "grpc.ErrClientConnClosing" handling
Fix

```
go test -v -tags cluster_proxy -run TestWatchErrConnClosed
```

with gRPC >= v1.10

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>
2018-06-15 14:47:11 -07:00
..
2018-04-16 17:36:00 -07:00