fix rsa_sign_saltlen_get_max_ex()

src/pk/rsa/rsa_sign_saltlen_get.c

@@ -29,7 +29,7 @@ int rsa_sign_saltlen_get_max_ex(int padding, int hash_idx, rsa_key *key)
   int ret = INT_MAX;
   LTC_ARGCHKVD(key != NULL);
 
-  if (hash_is_valid(hash_idx) &&
+  if ((hash_is_valid(hash_idx) == CRYPT_OK) &&
       (padding == LTC_PKCS_1_PSS))
   {
     ret = rsa_get_size(key);