Fix file hashing using more than one hash method
Fix file hashing using more than one hash method

The first hash was draining the io.Reader, causing the subsequents
hash algorithms to fail by hashing nil.

Myself5/mirrorbits,kib/mirrorbits,etix/mirrorbits,Myself5/mirrorbits,etix/mirrorbits,kib/mirrorbits,kib/mirrorbits,Myself5/mirrorbits,etix/mirrorbits