dirstateguard: remove layering violation around saving/restoring backup
This violation, which passes 'repo' object to dirstate, was introduced
by
59b5e8844eb0 and
020b12d591f3.
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.