Add missing hsprintf() after merge

Summary: rP4bd2ad

Test Plan: None.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4939
Fix undefined variable "none"

Summary: Assuming this is right?

Test Plan: No more exception error when viewing a revision.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4937
Use a serialize()-based cache instead of a JSON-based cache for changesets

Summary: These are full of PhutilSafeHTML objects now, which are destroyed by JSON serialization.

Test Plan: Dropped cache, then reloaded pages.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D4942
Restore merge of phutil_tag.
Merge branch 'phutil_tag'