mod_proxy_wstunnel: Fix the use of SSL connections with the "wss:" scheme.

                    PR55320.

Submitted by: Alex Liu <alex.leo.ca gmail.com>
Commited by: ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1594625 13f79535-47bb-0310-9956-ffa450edef68