Merge request commit creation: pass the encoding to Mercurial (Heptapod #71)
It's frequent that either the user (full) name of the commit message would have non-ASCII characters and up to now, it gave a failure (cannot merge).
We expect the encoding to be UTF-8 in almost all usages, but if we have a different one, chances are that the name would be identical for Ruby and Python, and this would still work.
--HG-- branch : heptapod