7f36b9d6e1
This reverts commit f2eda9a6a9.
Adding `-p` results in a world-readable file which we don't want for
e.g. `smtp_sasl_password_maps`:
> Keep the SASL client password file in /etc/postfix, and make the file
> read+write only for root to protect the username/password combinations
> against other users.[^1]
[^1]: https://www.postfix.org/SASL_README.html#client_sasl_enable