SECURITY (CVE-2013-4352): Fix a NULL pointer deference which allowed

      untrusted origin servers to crash mod_cache in a forward proxy configuration.

mod_cache: Avoid a crash with strcmp() when the hostname is not provided.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1523235 13f79535-47bb-0310-9956-ffa450edef68