Errors loading config files (relative paths) and in tail syntax

[48design]

Thank you for this nice backup script!

I ran into some trouble using it because the config files could not be loaded. I had to change the paths to the .main.config .sh and .database.config.cnf inside matomo_backup.sh from relative to absolute paths. Otherwise they could not be loaded.

Maybe this has something to do with server security or similar but the only way to make this work was this small change.

There is also an errors with the "delete old backups" code. "tail" gets the option for the number of files passed with two minus signs (--) which results in an error "unknown option".