mr: chaining to absolute paths

[Adam Spiers]

I notice that chaining to absolute paths does not work, e.g.:

    [$HOME/foo/bar]
    checkout = ...
    chain = true

This is due to the way the chaining code checks for an .mrconfig in
the chained repository:

        if ($parameter eq 'chain' &&
            length $dir && $section ne "DEFAULT" &&
            -e $dir.$section."/.mrconfig") {

Is this a feature or a bug?  I would have thought it would be useful
to chain to absolute paths.

Thanks,
Adam