5cb400bd72
Backup transports now provide the Backup Manager with a suggested name with which it can disambiguate any transport-specific bookkeeping that it needs to maintain. The Manager keeps separate application backup 'state blobs' for each transport now, preventing things from getting out of step if the device is switched among multiple transports. Also, the metadata backup agent is always invoked now on each backup pass. This is cheap when there is nothing to do, but also strongly ensures that we never wind up in a situation where a given transport destination has not been given all of the metadata necessary for the backup set.