Modernize DifferentialInlineCommentQuery

Summary:
Ref T7447. This class is currently a big mess with a lot of `withWeirdSpecialThingUsedInOnePlace()` type qualifiers.

Try to generalize/normalize it a bit.

Test Plan:
- Viewed inline comments.
- Created a new inline comment.
- Edited an inline comment.
- Marked an inline comment complete.
- Deleted, then undeleted an inline comment.
- Previewed inline comments.
- Viewed drafts as another user, verified they don't show up.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: yelirekim, epriestley

Maniphest Tasks: T7447

Differential Revision: https://secure.phabricator.com/D12483

src/applications/differential/controller/DifferentialInlineCommentEditController.php

@@ -39,13 +39,17 @@ final class DifferentialInlineCommentEditController
 
   protected function loadComment($id) {
     return id(new DifferentialInlineCommentQuery())
+      ->setViewer($this->getViewer())
       ->withIDs(array($id))
+      ->withDeletedDrafts(true)
       ->executeOne();
   }
 
   protected function loadCommentByPHID($phid) {
     return id(new DifferentialInlineCommentQuery())
+      ->setViewer($this->getViewer())
       ->withPHIDs(array($phid))
+      ->withDeletedDrafts(true)
       ->executeOne();
   }