completion: drop the hard coded list of config vars
[git] / contrib / credential /
drwxr-xr-x   ..
drwxr-xr-x - gnome-keyring
drwxr-xr-x - libsecret
drwxr-xr-x - netrc
drwxr-xr-x - osxkeychain
drwxr-xr-x - wincred