Stop caching target dir on Travis
Stop caching target dir on Travis

It doesn't make the builds faster and actually takes longer to
pack at the end since it always changes.

tildeio/turboruby,tildeio/turboruby,tildeio/helix,tildeio/helix,tildeio/turboruby,tildeio/helix,tildeio/turboruby,tildeio/helix