Presence of comments in pam-configs/ file cause several warnings when
invoking command `pam-auth-updates` (use of uninitialized value), and
then later the PAM configuration is broken:
- SSH login fails immediately (connection closed)
- opening a session with `sudo su -` is impossible (authorisation refused)
- and maybe more...
Without comments in /usr/share/pam-configs/yourdev, everything works as
expected, no warnings in `pam-auth-updates`, no authentication problems.