Fix: Corrected the used index in the iterator access function "config…

…_iterator_usage_type(...)".

Because the iterator access function "config_iterator_usage_type(...)" always returned NULL instead of the correct value, the used index in that function had to be corrected.

src/manage_sql_configs.c

@@ -3255,7 +3255,7 @@ config_iterator_nvts_growing (iterator_t* iterator)
  * @return The usage type of the config, or NULL if iteration is complete.
  *         Freed by cleanup_iterator.
  */
-DEF_ACCESS (config_iterator_usage_type, GET_ITERATOR_COLUMN_COUNT + 8);
+DEF_ACCESS (config_iterator_usage_type, GET_ITERATOR_COLUMN_COUNT + 6);
 
 /**
  * @brief Get predefined status from a config iterator.