Fix how setup.py identifies the Mercurial version.
There is a problem with setup.py where it will not identify the Mercurial
version properly when not being ran in within a repository even if
mercurial/__version__.py exists.
To fix, use mercurial.__version__.version when available before defaulting
to "unknown". (Using mercurial.util.version() is not an option due to a
dependency issue where osutil can be referenced before it is built.)
#!/bin/sh
hg init a
echo a > a/a
hg --cwd a ci -A -m a
hg clone a b
echo b > b/b
hg --cwd b ci -A -m b
chmod 100 a/.hg/store
hg --cwd b push ../a
chmod 700 a/.hg/store