Set php PATH for repository's hook

Summary:
~~Set PATH for repository's hook, so the environment.append-paths can used~~
repository's hook may can't find php path if user's profile like bash_profile is not loaded.

Test Plan: check the hook generated is contain the right path

Reviewers: epriestley, #blessed_reviewers

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7743

src/applications/repository/engine/PhabricatorRepositoryPullEngine.php

@@ -159,7 +159,13 @@ final class PhabricatorRepositoryPullEngine
 
     $root = dirname(phutil_get_library_root('phabricator'));
     $bin = $root.'/bin/commit-hook';
-    $cmd = csprintf('exec %s %s "$@"', $bin, $callsign);
+
+    $full_php_path = Filesystem::resolveBinary('php');
+    $cmd = csprintf(
+      'exec %s -f %s -- %s "$@"',
+      $full_php_path,
+      $bin,
+      $callsign);
 
     $hook = "#!/bin/sh\n{$cmd}\n";