Minor changes to horizon for Juno release

This change does the following:

- removes unnecessary symlinks (tested horizon w/out and see no 404s
  logged)
- ensures {{ install_lib_dir }}/static/ is owned by webserver user (as
  horizon tries to create {{ install_lib_dir }}/static/scss/assets)
Merge pull request #157 from mattt416/juno_horizon_fix

Minor changes to horizon for Juno release