fix segfault if response will have CNAME only

src/core/ngx_resolver.c

diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
index ab4dcda..52559a1 100644
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -1204,6 +1204,8 @@
         ngx_log_debug1(NGX_LOG_DEBUG_CORE, r->log, 0,
                        "resolver cname:\"%V\"", &name);
 
+        ngx_queue_remove(&rn->queue);
+
         rn->cnlen = (u_short) name.len;
         rn->u.cname = name.data;
         rn->valid = ngx_time() + r->valid;