Minor grammar glitch in a Websocket exception message.

[Igor Urisman]

As seen in 8.0.0 RC5:

java.lang.IllegalStateException: javax.websocket.DeploymentException:
Multiple Endpoints may not be deployed to using the same path
[/conntestCloseEndpoint]

IMHO, the message can't make up its mind between "to the same path" and
"using the same path".

-Igor.