res_http_websocket: websocket write timeout fails to fully disconnect

When writing to a websocket if a timeout occurred the underlying socket did not
get closed/disconnected. This patch makes sure the websocket gets disconnected
on a write timeout.

ASTERISK-24701 #close
Reported by: Matt Jordan
Review: https://reviewboard.asterisk.org/r/4412/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@431669 65c4cc65-6c06-0410-ace0-fbb531ad65f3