i#1649 rank order: avoid looking up module in dynamo_areas

Fixes a rank order violation when logging is enabled, which showed up in
the client.alloc test but could happen in other circumstances: we can't
look up module info while operating on dynamo_areas.

Fixes #1649

Review-URL: https://codereview.appspot.com/224880043

core/vmareas.c

@@ -737,7 +737,8 @@ print_vm_area(vm_area_vector_t *v, vm_area_t *area, file_t outf, const char *pre
         app_pc modbase =
             /* avoid rank order violation */
             IF_NO_MEMQUERY(v == all_memory_areas ? NULL :)
-            get_module_base(area->start);
+            /* i#1649: avoid rank order for dynamo_areas */
+            (v == dynamo_areas ? NULL : get_module_base(area->start));
         if (modbase != NULL &&
             /* avoid rank order violations */
             v != dynamo_areas &&