[pvr] fix marking recordings as watched or unwatched

@xhaggi @opdenkamp this bug has been around forever and I have a feeling this isn't the best way to fix it. Do you have any insight into what could be wrong?
isn't this refresh call needed? I don't have the code checked out, but unless SetRecordingsPlayCount() updates both the fileitem copy and the actual recording and this code picks up that change correctly, you'll still need it