add folder and publish configuratio to upload rosdistro_cache

I have already applied both changes to the running EC2 farm:

* http://ec2-54-67-30-249.us-west-1.compute.amazonaws.com:8080/view/Manage/job/indigo_rosdistro_cache/
* http://ec2-54-67-51-1.us-west-1.compute.amazonaws.com/rosdistro_cache/
Also needs a leading slash