Otherwise, we'd have to account for the additional `directory ' part
of a diagnostic like this:
fail-eperm: unexpected dignostic from `rm -f /tmp/.pcmcia';
got rm: cannot remove directory `/tmp/.pcmcia': Is a directory
expected rm: cannot remove `/tmp/.pcmcia': ...
It doesn't work with /bin/sh of Solaris5.6.
Use an explicit `export ARGV_0' instead.
[comparing actual and expected output]: Don't match the entire line,
but rather just the `rm: cannot remove `$dir/$f':' part.
Jim Meyering