Faye::WebSocket::API::ErrorEvent#data doesn't exist so don't try logging it.

In the case of a websocket error on the server, it would raise an error like `NoMethodError: undefined method `data' for #<Faye::WebSocket::API::ErrorEvent:0x00000002f062f0>`.

However, the code is written to simply log the error rather than raise an exception. This removes the call to the undefined method to get the desired behavior.