CLEANUP: always initialize the answer_list

Similar to the previous patch, the answer's list was only initialized the
first time it was added to a list, leading to bogus outdated pointer to
appear when debugging code is added around it to watch it. Let's make
sure it's always initialized upon allocation.
diff --git a/src/resolvers.c b/src/resolvers.c
index 564cd49..7381e75 100644
--- a/src/resolvers.c
+++ b/src/resolvers.c
@@ -991,6 +991,7 @@
 		answer_record->ar_item = NULL;
 		answer_record->last_seen = TICK_ETERNITY;
 		LIST_INIT(&answer_record->attached_servers);
+		LIST_INIT(&answer_record->list);
 
 		offset = 0;
 		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);