log_maint: Log errors on unlinking files
log_maint: Log errors on unlinking files

- In DB-Cleanup, unlinking fails
- Write unlink error to logfile as WARN
- Do not delete database entry when logfile deletion fails
This is for debugging - unlinking files _must_ work correctly in Release version

mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry