Don't pass md array UUID as member format UUID.
Don't pass md array UUID as member format UUID.

Related: rhbz#1070095

rhinstaller/blivet,jkonecny12/blivet,dwlehman/blivet,vojtechtrefny/blivet,rvykydal/blivet,dwlehman/blivet,AdamWill/blivet,jkonecny12/blivet,AdamWill/blivet,rhinstaller/blivet,vpodzime/blivet,vojtechtrefny/blivet,vpodzime/blivet,rvykydal/blivet