Attempt to be more helpful when using a bad ao2 object pointer.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@360626 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/astobj2.c

@@ -142,8 +142,13 @@ static inline struct astobj2 *INTERNAL_OBJ(void *user_data)
 	}
 
 	p = (struct astobj2 *) ((char *) user_data - sizeof(*p));
-	if (AO2_MAGIC != (p->priv_data.magic) ) {
+	if (AO2_MAGIC != p->priv_data.magic) {
-		ast_log(LOG_ERROR, "bad magic number 0x%x for %p\n", p->priv_data.magic, p);
+		if (p->priv_data.magic) {
+			ast_log(LOG_ERROR, "bad magic number 0x%x for %p\n", p->priv_data.magic, p);
+		} else {
+			ast_log(LOG_ERROR,
+				"bad magic number for %p. Object is likely destroyed.\n", p);
+		}
 		return NULL;
 	}