librbd: copy API should not inherit v1 image format by default

librbd: copy API should not inherit v1 image format by default

When copying from a v1 image, by default the new destination image
would be created using the v1 format. Since the creation of v1 images
is disallowed, this has been updated to default to using the v2
image format.

Fixes: https://tracker.ceph.com/issues/45518
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 69b6d5997e8c6a11739e4d5a32564e61eb2f470f)

Conflicts:
	src/librbd/internal.cc
- in nautilus, the call immediately preceding the change is
  "src->snap_lock.put_read()" whereas in master it is
  "src->image_lock.unlock_shared()"