Fix pingServer to always use the baseUrl

Remove "websockets" transport check from baseUrl assignment. pingServer - unlike getUrl() - always needs to use the base URL to create a proper http ping url (no Web Socket Urls are requested here).

This seems to fix a nasty bug when a Web Socket to a cross domain server times out or fails, would otherwise try to ping the client's page Web server using a relative path rather than the correct remote SignalR server.