Pass PutBlobOptions and TryReusingOptions by address in storage
Pass PutBlobOptions and TryReusingOptions by address in storage

... to avoid copies.

Keep the interfaces in terms of struct values, to make the
value semantics explicit (and maybe to help the compiler a bit
to show that the data doesn't need to be on a heap).

Signed-off-by: Miloslav Trmač <9c008e38982a5397deb855345fb164f0558459ae@redhat.com>

containers/image,containers/image