mint: bootrec: remove unused cache vars

Change-Id: I8f888391022d7426bafc53da6843efd486133afe
Change fs-type to auto (from vfat) so recovery works with ext4 sdcards

Change the fs-type in recoverys fstab to auto so it can also mount ext4 sdcards (which works fine in normal cm10.1)

Change-Id: Ib19a12e0fd4a698eaa7ceb1d0391376aa10c2966