Remove hashimoto@chromium.org from file_manager/webstore_widget_private OWNERS

For these directories, much better reviewers are available.

BUG=None

Review URL: https://codereview.chromium.org/1142383004

Cr-Commit-Position: refs/heads/master@{#330904}

chrome/browser/chromeos/extensions/file_manager/OWNERS

 # This should match chrome/browser/chromeos/file_manager/OWNERS
-hashimoto@chromium.org
 hirono@chromium.org
 kinaba@chromium.org
 mtomasz@chromium.org

chrome/browser/chromeos/file_manager/OWNERS

-hashimoto@chromium.org
 hirono@chromium.org
 kinaba@chromium.org
 mtomasz@chromium.org

chrome/browser/extensions/api/webstore_widget_private/OWNERS

 tbarzic@chromium.org
 
 # chrome/browser/chromeos/file_manager/OWNERS
-hashimoto@chromium.org
 hirono@chromium.org
 kinaba@chromium.org
 mtomasz@chromium.org