make "Land to..." button call diffusion.looksoon

Summary:
add looksoon call after every attempt at landing.

This includes failed attempts, to elevate "not a fast-forward" issues, although there are probably smarter things to be done about that.

Test Plan: Land, look at logs.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9518

src/applications/differential/controller/DifferentialRevisionLandController.php

@@ -141,6 +141,15 @@ final class DifferentialRevisionLandController extends DifferentialController {
     }
 
     $lock->unlock();
+
+    $looksoon = new ConduitCall(
+      'diffusion.looksoon',
+      array(
+        'callsigns' => array($repository->getCallsign())
+        ));
+    $looksoon->setUser($request->getUser());
+    $looksoon->execute();
+
     return $response;
   }