The `vcsh delete` command fails to remove files that have spaces in their filenames

Here are the steps to reproduce this bug&#65306;

~~~ bash
vcsh init foobar
touch 'foo bar'
vcsh foobar add 'foo bar'
vcsh foobar commit -m 'Add files'
vcsh foobar delete
~~~

The `foo bar` file still exists. It might be necessary to set a new IFS, similar to what is done in the [write_gitignore](https://github.com/RichiH/vcsh/blob/main/vcsh.in#L564) command.