[fix] Account for changes in npm-registry-client

When publishing, npm now makes a GET request to `/:pkg?write=true`
This prevents the `pkg` from including the querystring when checking
whether it exists in policy.{private,blacklist,whitelist}

The change to npm-registry-client can be found at https://github.com/npm/npm-registry-client/blob/master/lib/publish.js#L98