Echo WebRTC fails on /check

[fcecagno]

If /check is accessed on an HTTPS server, the WebRTC check fails because it always try to open a non-secure websocket. We should replicate the same implementation we have on the flash client, in which we use WS or WSS depending if the page is loaded on HTTP or HTTPS.

[fcecagno]

My mistake, actually we already use WSS if /check is loaded over HTTPS.

We have a problem of fail 1004 on Echo WebRTC metric, and I thought it was because of WSS, but that's not the case. It occurs over HTTP and HTTPS.