remove unused return value assignments

Fixes: #13555
Reviewed-by: NTomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13577)

crypto/asn1/bio_ndef.c

@@ -121,7 +121,7 @@ static int ndef_prefix(BIO *b, unsigned char **pbuf, int *plen, void *parg)
 
     ndef_aux->derbuf = p;
     *pbuf = p;
-    derlen = ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);
+    ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);
 
     if (*ndef_aux->boundary == NULL)
         return 0;

crypto/initthread.c

@@ -176,7 +176,7 @@ static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin)
             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
 
         if (hands == handsin) {
-            hands = sk_THREAD_EVENT_HANDLER_PTR_delete(gtr->skhands, i);
+            sk_THREAD_EVENT_HANDLER_PTR_delete(gtr->skhands, i);
             CRYPTO_THREAD_unlock(gtr->lock);
             return;
         }