* stable-5.2: Prepare 5.1.15-SNAPSHOT builds JGit v5.1.14.202011251942-r GC#deleteOrphans: log warning for deleted orphaned files GC#deleteOrphans: handle failure to list files in pack directory Ensure that GC#deleteOrphans respects pack lock Update API warning filters Remove unused imports Change-Id: Id9386846a202b5ae98dd602744963f8897ddaa8c