Re-add `Metadata.for_package` platform version truncation

This inadvertently got deleted in 0bfc7aa12.
Remove `homepage` from Artifact publisher path

Since any Artifactory repo used for storing Omnibus packages already
requires a custom layout we can safely remove any Maven-isms in the
path.
Merge pull request #265 from opscode/schisamo/artifactory-homepage-global-config

Remove `homepage` from Artifactory path