Adjust socache init interface to take sizing hints, and namespace tag

for memcache:

* modules/cache/ap_socache.h (struct ap_socache_hints): New structure.
  Change init callback to take namespace string and hints structure pointer.

* modules/cache/mod_socache_dc.c (socache_dc_init): Adjust accordingly.

* modules/cache/mod_socache_dbm.c (struct ap_socache_instance_t): Rename
  timeout field to expiry_interval.
  (socache_dbm_init, socache_dbm_create): Take expiry interval from
  hints rather than hard-code to 30.
  (socache_dbm_expire): Update for timeout field rename.

* modules/cache/mod_socache_shmcb.c (socache_shmcb_init): Adjust for
  hints and namespace; adjust subcache index sizing heuristics to use
  passed-in hints.

* modules/cache/mod_socache_memcache.c (struct ap_socache_instance_t):
  Add tag, taglen fields.
  (socache_mc_init): Store the passed-in namespace in instance
  structure.
  (mc_session_id2sz): Adjust to not take context, use configured
  tag as string prefix, and not use a return value.
  (socache_mc_store, socache_mc_retrieve, socache_mc_remove):
  Adjust for mc_session_id2sz interface changes.

* modules/ssl/ssl_scache.c (ssl_scache_init): Pass namespace and hints
  to socache provider init function.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@645978 13f79535-47bb-0310-9956-ffa450edef68