extend clone test to mock clone operation

extend clone test to mock clone operation

ops for clone:

{
            "op_num": 3,
            "op_name": "clone",
            "collection": "0.a_head",
            "src_oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/head\/\/0",
            "dst_oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/2\/\/0"
        },
        {
            "op_num": 4,
            "op_name": "setattr",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/2\/\/0",
            "name": "_",
            "length": 258
        },
        {
            "op_num": 5,
            "op_name": "rmattr",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/2\/\/0",
            "name": "snapset"
        },
        {
            "op_num": 6,
            "op_name": "op_setallochint",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/head\/\/0",
            "expected_object_size": "4194304",
            "expected_write_size": "4194304"
        },
        {
            "op_num": 7,
            "op_name": "write",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/head\/\/0",
            "length": 4096,
            "offset": 4024,
            "bufferlist length": 4096
        },
        {
            "op_num": 8,
            "op_name": "setattr",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/head\/\/0",
            "name": "_",
            "length": 273
        },
        {
            "op_num": 9,
            "op_name": "setattr",
            "collection": "0.a_head",
            "oid": "573db18a\/rbd_data.100c6b8b4567.0000000000000000\/head\/\/0",
            "name": "snapset",
            "length": 91
        }
    ]
}

Signed-off-by: xinxin shu <xinxin.shu@intel.com>