Merge behavior-show-more into behavior-populate

Summary: Ref T2009. It doesn't make sense to have these as separate behaviors. We require a ChangesetViewManager to track view parameter state.

Test Plan: Interacted with changesets in Phriction, Differential and Diffusion.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T2009

Differential Revision: https://secure.phabricator.com/D11979

src/applications/phriction/controller/PhrictionDiffController.php

@@ -108,7 +108,6 @@ final class PhrictionDiffController extends PhrictionController {
     Javelin::initBehavior('differential-populate', array(
       'changesetViewIDs' => array($output->getID()),
     ));
-    Javelin::initBehavior('differential-show-more');
 
     $slug = $document->getSlug();