#2021 - Cleanup thumb_dirty and resize_dirty instances.

- g2_import: changed "false" assignment to "0" assignment for consistency.
- admin_theme_options: removed unused variables (they're called/used nowhere else).
- graphics: removed stanza that clears thumb_dirty and resize_dirty and returns
if we have no ops.  This has no effect on Gallery currently (for one,
graphics::generate doesn't normally get called on an item with no dirty flags),
but can inconsistently set resize_dirty of albums and movies to 0 where it's
otherwise left at 1.  Going forward, it may be useful to be consistent here.
- gallery_installer: added v57 stanza to correct any resize_dirty flags of
movies/albums that were previously reset to 0.
- module.info, install.sql: update to v57

modules/gallery/controllers/admin_theme_options.php

@@ -34,7 +34,6 @@ class Admin_Theme_Options_Controller extends Admin_Controller {
       module::set_var("gallery", "page_size", $form->edit_theme->page_size->value);
 
       $thumb_size = $form->edit_theme->thumb_size->value;
-      $thumb_dirty = false;
       if (module::get_var("gallery", "thumb_size") != $thumb_size) {
         graphics::remove_rule("gallery", "thumb", "gallery_graphics::resize");
         graphics::add_rule(
@@ -45,7 +44,6 @@ class Admin_Theme_Options_Controller extends Admin_Controller {
       }
 
       $resize_size = $form->edit_theme->resize_size->value;
-      $resize_dirty = false;
       if (module::get_var("gallery", "resize_size") != $resize_size) {
         graphics::remove_rule("gallery", "resize", "gallery_graphics::resize");
         graphics::add_rule(