Log Message:
py-hg-evolve: update to 10.4.0.

This is a feature release. The most notable changes are: evolve
will now produce the same result regardless of revision numbers
when resolving content-divergence; an annoying topic bug that
sometimes prevented various history-rewriting commands from completing
with a KeyError was fixed. See
https://bz.mercurial-scm.org/show_bug.cgi?id=6500 for details. Also
compatibility with Mercurial 4.6 was dropped in this release.