Fixing `--author` in orepan2-inject

Before this change:

    root@dc597dbfd34a:~# rm -rf /darkpan; orepan2-inject --author=asdf Test::Whitespaces /darkpan
    Wrote 1 from Test::Whitespaces
    [INFO] Could not find useful meta from '/darkpan/authors/id/D/DU/DUMMY/Test-Whitespaces-1.2.1.tar.gz'
    [INFO] Scanning for provided modules...
    root@dc597dbfd34a:~#

After this change:

    root@dc597dbfd34a:~# rm -rf /darkpan/; perl -Ilib script/orepan2-inject --author=asdf Test::Whitespaces /darkpan
    Wrote 1 from Test::Whitespaces
    [INFO] Could not find useful meta from '/darkpan/authors/id/A/AS/ASDF/Test-Whitespaces-1.2.1.tar.gz'
    [INFO] Scanning for provided modules...
    root@dc597dbfd34a:~#

The difference is in path where the file is stored.