artifact path mismatches with distnames for TRIAL

[miyagawa]

Rather than using the original distribution name, Carmel imports the directories from Menlo's latest-build directory, which creates directory names based on the directory names in the CPAN module's tar balls.

This could lead to inconsistencies when searching for distnames with $repo->find_dist($package, $distname) for trial releases, because dist name can be Foo-Bar-1.000-TRIAL when the directory can simply be Foo-Bar-1.000.