fix favoriting again a comic
fix favoriting again a comic

Refavoriting a comic was leading to the deletion of some previous data
and so the strip was always redownloaded and marked as new
proper fix for 93d1d549ca94c2814258838bdd08c771d63f2073

tardypad/daily-comics,tardypad/sailfishos-daily-comics,tardypad/daily-comics,tardypad/sailfishos-daily-comics,tardypad/sailfishos-daily-comics,tardypad/daily-comics