Summary: Deletion is a possibly time-intensive process, especially with large files that are backed by high-latency, chunked storage (such as S3). Even ~200mb objects take minutes to delete, which makes for an unhappy experience. Fixes T10828. Test Plan: Delete a large file, and stare in awe of the swiftness with which I am redirected to the main file application. Reviewers: #blessed_reviewers, epriestley Reviewed By: #blessed_reviewers, epriestley Subscribers: thoughtpolice, Korvin Maniphest Tasks: T10828 Differential Revision: https://secure.phabricator.com/D15743