`pkgdev manifest` do not create manifests for /files, only for ebuilds

[vitaly-zdanevich]

I do not understand - this is expected behavior or a bug, if expected - should print some message for a user.

Also tried

# pkgdev manifest files/myfile

and got:

pkgdev manifest: error: file is not an ebuild: '/var/db/repos/my/net-libs/bla/bla/files/myfile',

### Tasks

[vitaly-zdanevich]

Generated after removing of Manifest.