Note that if you perform the above to reproduce, and then remove the symbolic links, you'll also need to forcefully reinstall the horizon package as it is polluted by the symbolic link / collectstatic:
pip uninstall horizon rm -rf /usr/local/lib/python2.7/dist-packages/horizon pip install . -c ../requirements/upper-constraints.txt
Note that if you perform the above to reproduce, and then remove the symbolic links, you'll also need to forcefully reinstall the horizon package as it is polluted by the symbolic link / collectstatic:
pip uninstall horizon lib/python2. 7/dist- packages/ horizon /upper- constraints. txt
rm -rf /usr/local/
pip install . -c ../requirements