Move DifferentialRevision to application PHIDs

Summary: Ref T2715.

Test Plan: Used `phid.lookup` and `phid.query` to load handles. Grepped for `PHID_TYPE_DREV`.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2715

Differential Revision: https://secure.phabricator.com/D6509

resources/sql/patches/migrate-differential-dependencies.php

@@ -8,7 +8,7 @@ foreach (new LiskMigrationIterator($table) as $rev) {
   $id = $rev->getID();
   echo "Revision {$id}: ";
 
-  $deps = $rev->getAttachedPHIDs(PhabricatorPHIDConstants::PHID_TYPE_DREV);
+  $deps = $rev->getAttachedPHIDs(DifferentialPHIDTypeRevision::TYPECONST);
   if (!$deps) {
     echo "-\n";
     continue;