Changed 'diffusion.getrecentcommitsbypath' to return only the direct and child

changes.

Summary:
It was incorrectly returning copies.

Test Plan:
Tested that the conduit call for 'tfb/trunk/www/last_min_rev.txt' matches
https://phabricator.fb.com/diffusion/E/history/tfb/trunk/www/last_min_rev.txt

Reviewed By: jungejason
Reviewers: jungejason, epriestley, aran
CC: aran, jungejason
Differential Revision: 340

src/applications/conduit/method/diffusion/getrecentcommitsbypath/ConduitAPI_diffusion_getrecentcommitsbypath_Method.php

@@ -50,6 +50,8 @@ class ConduitAPI_diffusion_getrecentcommitsbypath_Method
       )
     )
     ->setLimit(self::RESULT_LIMIT)
+    ->needDirectChanges(true)
+    ->needChildChanges(true)
     ->loadHistory();
 
     $raw_commit_identifiers = mpull($history, 'getCommitIdentifier');