fix ticket:5431

- do NOT, i repeat, do NOT reset memory_pools->used in pool_free_extra_list
  as this will basically remove all the allocated stuff from the current
  memory pool

OMCompiler/SimulationRuntime/c/gc/memory_pool.c

@@ -126,14 +126,19 @@ static int pool_free_extra_list(void)
   if (NULL == memory_pools) {
     return 0;
   }
+
   freelist = memory_pools->next;
   while (freelist) {
     list *next = freelist->next;
     omc_alloc_interface.free_uncollectable(freelist->memory);
     omc_alloc_interface.free_uncollectable(freelist);
     freelist = next;
   }
-  memory_pools->used = 0;
+
+  /* adropo: why on earth would you do this?!?
+   * See ticket #5431 for an error generated by this error.
+   * memory_pools->used = 0;
+   */
   memory_pools->next = 0;
   return 0;
 }