Remove leading "/" so that "git cat-file" works

Summary:
When the absolute path is used for load file (loadFileContent(()), it fails in git. For example:

  /var/repo/page_admin_app
  > git cat-file blob '4d6c03923006d6c444660f2c734fe03e10fd20bd':'/ios/PageAdminApp/Resources/splash/De           fault-Portrait@2x~ipad.png'
  fatal: Not a valid object name 4d6c03923006d6c444660f2c734fe03e10fd20bd:/ios/PageAdminApp/Resources/s           plash/Default-Portrait@2x~ipad.png

This is breaking the auto-closing for about 8 revisions like

https://phabricator.fb.com/rPPA4d6c03923006d6c444660f2c734fe03e10fd20bd ...
https://phabricatorcator.fb.com/rPPA51acb7e482aab0c491b530ed19dddc741d50f673 ...

Test Plan:
- reparsed https://phabricator.fb.com/rPPA4d6c03923006d6c444660f2c734fe03e10fd20bd successfully with corresponding differential revision being closed.

- verified that without leading '/', loadFileContent for svn still works. Both of the following commands worked (note the double '/' right before 'tfb':

  svn cat svn+ssh://svn.vip.facebook.com/svnroot//tfb/trunk/www/flib/intern/cachearchiver/regenerators/wurfl/CacheArchiveWurflRegenerator.php@579700
  svn cat svn+ssh://svn.vip.facebook.com/svnroot/tfb/trunk/www/flib/intern/cachearchiver/regenerators/wurfl/CacheArchiveWurflRegenerator.php@579700

Reviewers: vrana

Reviewed By: vrana

CC: nh, aran, epriestley

Differential Revision: https://secure.phabricator.com/D2847

src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php

@@ -221,12 +221,14 @@ abstract class PhabricatorRepositoryCommitMessageParserWorker
       'commit');
     foreach ($vs_diff->loadChangesets() as $changeset) {
       $path = $changeset->getAbsoluteRepositoryPath($repository, $vs_diff);
+      $path = ltrim($path, '/');
       $vs_changesets[$path] = $changeset;
     }
 
     $changesets = array();
     foreach ($diff->getChangesets() as $changeset) {
       $path = $changeset->getAbsoluteRepositoryPath($repository, $diff);
+      $path = ltrim($path, '/');
       $changesets[$path] = $changeset;
     }