libgit2/pygit2 — pull request #331 by carlosmn (2014-01-28 18:04:44+00:00)
Title: Remove useless constructors

The Reference, Branch, ConfigIter and Walker types were allowed to be created by the
user, but no constructor was set, and the default values are either
meaningless (in the case of Reference/Branch) or would cause a segfault
as soon as one tried to use them (ConfigIter and Walker).

Remove the constructor from these types, as they don't serve a purpose
and can only be used by mistake.