Make AphrontErrorView work on devices

Summary:
This is the last Paste UI element that doesn't work properly on tablets/phones. Make it flexible.

Also add empty states to Paste.

Test Plan: Viewed various errors, and `/uiexample/errors/`.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D3429

src/applications/diffusion/controller/DiffusionCommitController.php

@@ -72,7 +72,6 @@ final class DiffusionCommitController extends DiffusionController {
       $subpath = $commit_data->getCommitDetail('svn-subpath');
 
       $error_panel = new AphrontErrorView();
-      $error_panel->setWidth(AphrontErrorView::WIDTH_WIDE);
       $error_panel->setTitle('Commit Not Tracked');
       $error_panel->setSeverity(AphrontErrorView::SEVERITY_WARNING);
       $error_panel->appendChild(
@@ -156,7 +155,6 @@ final class DiffusionCommitController extends DiffusionController {
     $pane_id = null;
     if ($bad_commit) {
       $error_panel = new AphrontErrorView();
-      $error_panel->setWidth(AphrontErrorView::WIDTH_WIDE);
       $error_panel->setTitle('Bad Commit');
       $error_panel->appendChild(
         phutil_escape_html($bad_commit['description']));
@@ -166,7 +164,6 @@ final class DiffusionCommitController extends DiffusionController {
       // Don't render anything else.
     } else if (!count($changes)) {
       $no_changes = new AphrontErrorView();
-      $no_changes->setWidth(AphrontErrorView::WIDTH_WIDE);
       $no_changes->setSeverity(AphrontErrorView::SEVERITY_WARNING);
       $no_changes->setTitle('Not Yet Parsed');
       // TODO: This can also happen with weird SVN changes that don't do