Rebuild descriptor when DirCache is {dis,en}abled

src/or/config.c

@@ -4314,7 +4314,8 @@ options_transition_affects_descriptor(const or_options_t *old_options,
       !opt_streq(old_options->MyFamily, new_options->MyFamily) ||
       !opt_streq(old_options->AccountingStart, new_options->AccountingStart) ||
       old_options->AccountingMax != new_options->AccountingMax ||
-      public_server_mode(old_options) != public_server_mode(new_options))
+      public_server_mode(old_options) != public_server_mode(new_options) ||
+      old_options->DirCache != new_options->DirCache)
     return 1;
 
   return 0;