Replace uid/gid in export_user_files.py with constants...
Replace uid/gid in export_user_files.py with constants...

... for readability.

chambm/docker-galaxy-stable,afgane/docker-galaxy-stable,bgruening/docker-galaxy-stable,shiltemann/docker-galaxy-stable,bgruening/docker-galaxy-stable,bgruening/docker-galaxy-stable,kellrott/docker-galaxy-stable,kellrott/docker-galaxy-stable,shiltemann/docker-galaxy-stable,shiltemann/docker-galaxy-stable,chambm/docker-galaxy-stable,afgane/docker-galaxy-stable,kellrott/docker-galaxy-stable,chambm/docker-galaxy-stable,afgane/docker-galaxy-stable