app-admin/checkrestart: Workaround a problem with finding pkg name

app-admin/checkrestart: Workaround a problem with finding pkg name

The output of qfile is used by checkrestart to get a list of programs
owning certain files. A feature of qfile is that its output is dependent
on the current working directory. Some of the files in its output aren't
programs and checkrestart crashed. This patch sets the cwd to / for the
qfile subprocess, so its output is as expected.

Thanks to Karl <karlc@keckec.com> for investigating the issue, providing
patch and explanation above.

This not a final soluation for the problem, but it's a good workaround
given there are not so many processes named after any directory in /.

Gentoo-Bug: 548920

Package-Manager: portage-2.3.0