[giow] (2) Make sure WebSocket connections that can't honour the subprotocol don't get established (looks like this got broken in the protocol spec at some point)
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=23576
Affected topics: HTML

git-svn-id: http://svn.whatwg.org/webapps@8232 340c8d12-0b0e-0410-8428-c7bf67bfef74