Nodes from cache could be changed by traverser, if no objectID specified.
So it is required to return copy of cache's slice.
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
As EC put request may be processed only by container node, so sign requests
with current node private to not to perform APE checks.
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>