Using an 'artifact' repo results in bad links and bad dist files

Using an artifact repository results in bad links, and misnamed files in the dist directory.

``` json
{
"name": "My Repository",
"homepage": "http://localhost/artifacts",
"repositories": [
{ "type": "artifact", "url": "./packages" }
],
"archive": {
"directory": "dist",
"format": "tar"
},
"require-all": true
}
```

creates links like: `http://localhost/artifacts/dist/local-mypackage-1.0.5.7-local-mypackage-1.0.5.7.zip.tar` as well as the corresponding `.zip.tar` files in `dist`

Reproduce the issue with the JSON configuration shown, using an artifact repository and the tar archive settings. Trace the archive and link generation from that configuration; done means the generated dist filenames and repository URLs no longer contain the duplicated package name or the unexpected .zip.tar suffix.

Written by the indexing model from the issue text.