add overlay config schema registry

servers/slapd/bconfig.c

@@ -195,12 +195,25 @@ static OidRec OidMacros[] = {
 };
 
 /*
+ * Backend/Database registry
+ *
  * OLcfg{Bk|Db}{Oc|At}:0		-> common
  * OLcfg{Bk|Db}{Oc|At}:1		-> bdb
  * OLcfg{Bk|Db}{Oc|At}:2		-> ldif
  * OLcfg{Bk|Db}{Oc|At}:3		-> ldap?
  */
 
+/*
+ * Overlay registry
+ *
+ * OLcfgOv{Oc|At}:1			-> syncprov
+ * OLcfgOv{Oc|At}:2			-> pcache
+ * OLcfgOv{Oc|At}:3			-> chain
+ * OLcfgOv{Oc|At}:4			-> accesslog
+ * OLcfgOv{Oc|At}:5			-> valsort
+ * OLcfgOv{Oc|At}:6			-> smbk5pwd (use a separate arc for contrib?)
+ */
+
 /* alphabetical ordering */
 
 static ConfigTable config_back_cf_table[] = {