Remove unnecessary empty checks from willFilterPage()

Summary: Fixes T3600. These checks are obsolete after D6512.

Test Plan: Syntax / static / inspection.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3600

Differential Revision: https://secure.phabricator.com/D6563

src/applications/differential/query/DifferentialRevisionQuery.php

@@ -360,10 +360,6 @@ final class DifferentialRevisionQuery
   }
 
   public function willFilterPage(array $revisions) {
-    if (!$revisions) {
-      return $revisions;
-    }
-
     $table = new DifferentialRevision();
     $conn_r = $table->establishConnection('r');