Backups of cleaned repositories grow as we make clean syncs

[SergioBertolinSG]

Every time a user changes server or user and chooses to make a clean sync a new folder called oC_bak(_n) is created. I think this generates a lot of thrash, having in mind that the user has choosed a clean synchronization instead of keeping the files.
I suggest to erase the last backup folder and create a new one, keeping only the last backup of the folder 'cleaned'.