Does anybody have any use of error_log?

Hi,

I've created https://github.com/rdiff-backup/rdiff-backup/issues/548
because the code for error_log is just standing in my (simplification) way.

If anybody is using this file for any good reason, please add your
arguments to the above issue, else I'll remove the "feature" faster than
you can spell 'rdiff-backup'...

Thanks, Eric