Aphlict - fix incrementation of _messagesIn

Summary: Ref T7124. The local version of this in the handler of 'end' was incremented rather than the global one.

Test Plan: Sending test notifications did not increment the messages.in value before this patch even if it should have. With the patch sending test notifications does increment messages.in.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7124

Differential Revision: https://secure.phabricator.com/D11648