Log Message:
py-dulwich: updated to 0.18.5

0.18.5:
BUG FIXES
* Fix cwd for hooks.
* Fix setting of origin in config when non-standard origin is passed into
  ``Repo.clone``.
* Prevent setting SSH arguments from SSH URLs when using SSH through a
  subprocess. Note that Dulwich doesn't support cloning submodules.
  (CVE 2017-1000117)

IMPROVEMENTS
* Silently ignored directories in ``Repo.stage``.

API CHANGES
* GitFile now raises ``FileLocked`` when encountering a lock
  rather than OSError(EEXIST).