RGW - Fix copy_obj handling of obj_ctx

RGW - Fix copy_obj handling of obj_ctx

Fixes: https://tracker.ceph.com/issues/66286
(Line added by Gabriel)

In RadosStore, the source and dest objects in the copy_object() call
used to share an obj_ctx.  When obj_ctx was removed from the SAL API,
they each got their own, but RGWRados::copy_obj() still assumed they
shared one.

Pass in each one separately, and use the correct one for further calls.

Signed-off-by: Daniel Gryniewicz <dang@fprintf.net>
Signed-off-by: Gabriel BenHanokh <gbenhano@redhat.com>