Join & Leave Serf processing happens in a separate goroutine and there
are cases as in https://github.com/docker/libnetwork/issues/985, it can
cause lookup failures when endpoint delete processing happens before
Serf gets a chance to handle the leave processing.
The fix is to avoid such lookups in this goroutine, but handle the
endpoint and network objects directly.
Signed-off-by: Madhu Venugopal <madhu@docker.com>