In previous implementation wrapper over the Container contract's client
returned the signature of the eACL table in addition to itself. After recent
changes in API Go lib table carries its signature. Thus, it is redundant to
return the table signature separately.
Make `Wrapper.GetEACL` method to return only `eacl.Table` with error.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>