lib/model: Actually break puller loop on context cancel (#7492)
lib/model: Actually break puller loop on context cancel (#7492)

Current break does nothing (breaks the select).
syncthing/syncthing,wweich/syncthing,syncthing/syncthing,syncthing/syncthing,wweich/syncthing,syncthing/syncthing,wweich/syncthing,syncthing/syncthing,wweich/syncthing,syncthing/syncthing