dotgit: ignore filenames that don't match a hash
dotgit: ignore filenames that don't match a hash

For both packfiles and object files.

Issue: keybase/client#11366
Signed-off-by: Jeremy Stribling <becc0f37b8e6d4ee27d6d921b811f71a56c73178@alum.mit.edu>

src-d/go-git,mcuadros/go-git,go-git/go-git,src-d/go-git,mcuadros/go-git,go-git/go-git