fix(intel/manifest): Do not reuse Hash instance.
fix(intel/manifest): Do not reuse Hash instance.

The problem is that method Hash returns the same instance
of hash.Hash. It means if the instance was used before, it
might be left in a dirty state. It creates quite unobvious
bugs.

Signed-off-by: Dmitrii Okunev <74d81ae1898d935b77a01158fdef590f9767e0f5@fb.com>

linuxboot/fiano