Remove helper method that creates regex filter.
Remove helper method that creates regex filter.

This will discourage the creation of default regex filters, which
exhibit poor performance.

duplicati/duplicati,mnaiman/duplicati,duplicati/duplicati,sitofabi/duplicati,mnaiman/duplicati,sitofabi/duplicati,mnaiman/duplicati,duplicati/duplicati,sitofabi/duplicati,duplicati/duplicati,mnaiman/duplicati,mnaiman/duplicati,sitofabi/duplicati,sitofabi/duplicati,duplicati/duplicati