[close #108] Br debug checksum cmd (#114) * implement debug checksum cmd Signed-off-by: haojinming <jinming.hao@pingcap.com> * add api version check Signed-off-by: haojinming <jinming.hao@pingcap.com> add warning Signed-off-by: haojinming <jinming.hao@pingcap.com> revert changes Signed-off-by: haojinming <jinming.hao@pingcap.com> * move common functions Signed-off-by: haojinming <jinming.hao@pingcap.com>