Add a "dateCreated" key to Maniphest

Summary: Depends on D6952. Unpunts there since I'm rolling into a swamp full of schema changes.

Test Plan: Issued date-constrained query and saw key as a candidate.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D6954

resources/sql/patches/20130912.maniphest.2.created.sql

···
+ALTER TABLE {$NAMESPACE}_maniphest.maniphest_task
+  ADD KEY `key_dateCreated` (dateCreated);

src/applications/maniphest/query/ManiphestTaskQuery.php

···
     $where[] = $this->buildXProjectWhereClause($conn);
     $where[] = $this->buildFullTextWhereClause($conn);
 
-    // TODO: Add a key for this the next time we hit this table.
-
     if ($this->dateCreatedAfter) {
       $where[] = qsprintf(
         $conn,

src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php

···
         'type' => 'sql',
         'name' => $this->getPatchPath('20130912.maniphest.1.touch.sql'),
       ),
+      '20130912.maniphest.2.created.sql' => array(
+        'type' => 'sql',
+        'name' => $this->getPatchPath('20130912.maniphest.2.created.sql'),
+      ),
     );
   }
 }