Upgrade stops and offers a recovery.
Before that in upgrade log I can see successful copying:
...
classes/.htaccess
config/.htaccess
config/xml/.htaccess
css/.htaccess
and after that error with /docs/.htaccess
I can't find such folder in PS directory...maybe I don't understand something? Because if it is not in PS folder, than why presta trying to upgrade that? (outside PS folder I also can't find such folder)