PR56870: authzprovideralias-defined authz provier can't be used in a virtualhost

apply the same workaround from mod_authn_core r1554995 so r->server has our hash.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1618851 13f79535-47bb-0310-9956-ffa450edef68