Add support to mod_ssl for a distributed session cache using

Add support to mod_ssl for a distributed session cache using
distcache.

* LAYOUT: Update for removal of scache_shmht and addition of scache_dc.

* modules/ssl/config.m4: Check for libdistcache; build ssl_scache_dc.lo.

* modules/ssl/mod_ssl.dsp: Build ssl_scache_dc (with luck).

* modules/ssl/mod_ssl.h: Add SSL_SCMODE_DC and scache_dc_* prototypes.

* modules/ssl/ssl_engine_config.c (ssl_cmd_SSLSessionCache): Allow
use of dc: argument.

* modules/ssl/ssl_scache_dc.c: New file.

* modules/ssl/ssl_scache.c (ssl_scache_init, ssl_scache_kill,
ssl_scache_store, ssl_scache_retrieve, ssl_scache_remove,
ssl_ext_status_hook): Hook into scache_dc.

Submitted by: Geoff Thorpe <geoff@geoffthorpe.net>

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk/modules/ssl@102227 13f79535-47bb-0310-9956-ffa450edef68