edd: Fix UnboundLocalError when trying to close fd in collect_mbrs
edd: Fix UnboundLocalError when trying to close fd in collect_mbrs

The "fd" variable is not defined when the "os.open" fails (e.g.
when the device we try to open doesn't exist).

jkonecny12/blivet,vojtechtrefny/blivet,vojtechtrefny/blivet,rvykydal/blivet,rvykydal/blivet,jkonecny12/blivet