Update to efivar 31
    Work around NVMe EUI sysfs change
    Provide some oldish version strings we should have kept.
    lots of overflow checking on our pointer math in dp parsing
    fix major/minor device number handling in the linux code
    Do better formatting checks for MBR partitions
    Fixes for gcc 7
    
    Signed-off-by: Peter Jones <pjones@redhat.com>