rust: Move DirstateEntry to its own module … and RawEntry to the dirstate::parsers module, the only one that uses it. Differential Revision: https://phab.mercurial-scm.org/D11457

extensions: prevent a crash on py3 with a `minimumhgversion` str value The expectation is that this field is bytes, but unported extensions are a thing and it shouldn't explode on a bad value. We already do this transformation in the version reporting mechanism. Differential Revision: https://phab.mercurial-scm.org/D11476