R1:22b2b8eb893a

Fix a bad call in file chunk destruction

Summary: This signature changed at some point after I tested things and I didn't catch it.

Test Plan: Destroyed a chunked large file with `bin/remove`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D12152