Sorcery: Log when old config remains in use

This adds a log message notifying the user that a stale configuration
is in place upon reload when a config object fails to load. This
situation can end up causing confusion when the object failed to load
but exists from a previous config load especially when the old config
is significantly different from the new config.

Review: https://reviewboard.asterisk.org/r/4250/
Reported by: Thomas Thompson
........

Merged revisions 429429 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@429430 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_sorcery_config.c

@@ -284,6 +284,8 @@ static void sorcery_config_internal_load(void *data, const struct ast_sorcery *s
 			if (!(obj = sorcery_config_retrieve_id(sorcery, data, type, id))) {
 				continue;
 			}
+
+			ast_log(LOG_NOTICE, "Retaining existing configuration for object of type '%s' with id '%s'\n", type, id);
 		}
 
 		ao2_link_flags(objects, obj, OBJ_NOLOCK);