Throw a richer exception when updating tasks with expired leases

Summary: Include task ID and class when raising this exception. I took a brief stab at doing this generically, but (a) we specifically raise this exception outside of normal try/catch because we can't follow normal recovery rules for it and (b) we don't have a reasonable PhutilProxyException or similar right now which would preserve stack traces, and don't have builtin exception nesting support until PHP 5.3.

Test Plan: Faked this exception, verified we get more information in the logs.

Reviewers: btrahan, vrana

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2193

Differential Revision: https://secure.phabricator.com/D4205