Re-create links seems to fail

[pelson]

Traceback (most recent call last):
File "conda-gitenv", line 9, in
load_entry_point('conda-gitenv==0.1.1.dev1+g677f4f6', 'console_scripts', 'conda-gitenv')()
File "lib/python3.4/site-packages/conda_gitenv/cli.py", line 22, in main
return args.function(args)
File "lib/python3.4/site-packages/conda_gitenv/deploy.py", line 144, in handle_args
deploy_repo(repo, args.target)
File "lib/python3.4/site-packages/conda_gitenv/deploy.py", line 131, in deploy_repo
os.symlink(label_target, label_location)
FileExistsError: [Errno 17] File exists: '2015_12_16-2' -> 'default/current'