Fix PR 17864, and also fixes a SEGV problem when SHMHT was used.

The porting of the code from mod_ssl 1.3.x was still incomplete, and depended
upon a complete implentation of apr_shm (hence pieces of code was #if 0'ed out).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@98990 13f79535-47bb-0310-9956-ffa450edef68