tests/bundles/rename.sh

run-tests: avoid set PYTHONUSERBASE environment variable to None

According to python documentation, get_config_var can return None and it was
during running mercurial tests under a virtual environment with the local built
mercurial installed as a python package with `pip install -e .`.

On the other hand, if mercurial is installed in the user library folders with
`pip install --local -e .` the issue doesn't reproduce.

The fallback is that it will just set an empty string and everything should work
as before, according to https://www.python.org/dev/peps/pep-0370/:

    The path to the user base directory can be overwritten with the environment
    variable PYTHONUSERBASE. The default location is used when PYTHONUSERBASE is
    not set or empty.

#!/bin/sh

#  @  3: 'move2'
#  |
#  o  2: 'move1'
#  |
#  | o  1: 'change'
#  |/
#  o  0: 'add'

hg init copies
cd copies
echo a > a
echo b > b
echo c > c
hg ci -Am add
echo a >> a
echo b >> b
echo c >> c
hg ci -m change
hg up -qC 0
hg cp a d
hg mv b e
hg mv c f
hg ci -m move1
hg mv e g
hg mv f c
hg ci -m move2
hg bundle -a ../renames.hg
cd ..