Remove obsolete disk ownership workaround for Debian bug #645466

Originally created by @anonym on #11534 (Redmine)

The issue we worked around has been fixed in 2014 in systemd 204-9:

   * Drop our Debian specific 60-persistent-storage{,-tape}.rules and use the
     upstream rules. They are compatible and do a superset of the
     functionality. (Closes: #645466)