lib/versioner: Interpret versions path relative to folder path (fixes #4188)
lib/versioner: Interpret versions path relative to folder path (fixes #4188)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4243

wweich/syncthing,syncthing/syncthing,uok/syncthing,rumpelsepp/syncthing,rumpelsepp/syncthing,lkwg82/syncthing,wweich/syncthing,uok/syncthing,xduugu/syncthing,jryans/syncthing,AudriusButkevicius/syncthing,imsodin/syncthing,uok/syncthing,rumpelsepp/syncthing,jryans/syncthing,AudriusButkevicius/syncthing,AudriusButkevicius/syncthing,AudriusButkevicius/syncthing,syncthing/syncthing,lkwg82/syncthing,jryans/syncthing,imsodin/syncthing,syncthing/syncthing,xduugu/syncthing,lkwg82/syncthing,syncthing/syncthing,syncthing/syncthing,rumpelsepp/syncthing,imsodin/syncthing,wweich/syncthing,uok/syncthing,jryans/syncthing,lkwg82/syncthing,xduugu/syncthing,wweich/syncthing,imsodin/syncthing,syncthing/syncthing,xduugu/syncthing,imsodin/syncthing