R1:4a45620b0458

Reload revisions before publishing mail about them

Fixes this, which only triggers on some kinds of mail:

```
Daemon 39819 STDE [Thu, 04 Jun 2015 02:56:38 +0000] [2015-06-04 02:56:38] EXCEPTION: (PhutilProxyException) Error while executing Task ID 902251. {>} (PhabricatorDataNotAttachedException) Attempting to access attached data on DifferentialRevision (via getActiveDiff()), but the data is not actually attached. Before accessing attachable data on an object, you must load and attach it.
Daemon 39819…