rgw/rados: rgw_rados_operate() takes version_t*

rgw/rados: rgw_rados_operate() takes version_t*

instead of calling ioctx.get_last_version() after a rados operation,
callers now pass version_t* as an output parameter. in the null_yield
case, that version is assigned to ioctx.get_last_version() as normal. in
the async case, we get the version out of librados::async_operate()'s
return value

Fixes: https://tracker.ceph.com/issues/63935
Signed-off-by: Casey Bodley <cbodley@redhat.com>