Only remove dvr recordings if stream urls change, and for shows that are marked as "live"

[tjenkinson]

Currently clicking update on a live stream page (from unchecking live for example) will cause all the dvr urls to be deleted (and dvr recordings deleted), because it assumes that the source stream urls have changed and therefore dvr recordings must not continue with the old urls. The new url's should be compared with the old ones to determine if they have actually changed.

Even if the source urls have changed dvr urls should only then be deleted for streams that are "live". If a stream has finished then there's no reason to remove the recording.