Log Message:
Updated py-dulwich to 0.14.1.

0.14.1	2016-07-05

 BUG FIXES

  * Fix regression removing untouched refs when pushing over SSH.
    (Jelmer Vernooij #441)

  * Skip Python3 tests for SWIFT contrib module, as it has not yet
    been ported.

0.14.0	2016-07-03

 BUG FIXES

  * Fix ShaFile.id after modification of a copied ShaFile.
    (Félix Mattrat, Jelmer Vernooij)

  * Support removing refs from porcelain.push.
    (Jelmer Vernooij, #437)

  * Stop magic protocol ref `capabilities^{}` from leaking out
    to clients. (Jelmer Vernooij, #254)

 IMPROVEMENTS

  * Add `dulwich.config.parse_submodules` function.

  * Add `RefsContainer.follow` method. (#438)