mod_slotmem_shm pool handling

[Joe Orton]

mod_slotmem_shm is creating a subpool of pconf ("gpool") in the 
pre_config hook.  It then hangs a cleanup off pconf in the post_config 
hook, which uses something with the structures in "gpool".

This doesn't work (and segfaults with APR pool debugging) because the 
gpool contents are invalidated by the time the cleanup runs.

Patch below moves the cleanup to the "gpool", which avoids the problem 
and doesn't seem to break anything else, but the subpool is never 
cleared or destroyed... so could we just remove the subpool altogether?  
(Is there is an unfullfilled intention to bound memory use across 
generations here perhaps?)

Index: mod_slotmem_shm.c
===================================================================
--- mod_slotmem_shm.c   (revision 1136832)
+++ mod_slotmem_shm.c   (working copy)
@@ -643,7 +643,7 @@
 static int post_config(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp,
                        server_rec *s)
 {
-    slotmem_shm_initialize_cleanup(p);
+    slotmem_shm_initialize_cleanup(gpool);
     return OK;
 }