8. GetLocalBlockHead 获取子链区块块头数据

* 参数: hid 超块号

id 子块号

chain_num 子链号

* 例子: http://127.0.0.1:8080/GetLocalBlockHead?hid=10&id=1&chain_num=1

* 返回例子：

{
  "app_type":[0],
  "block_size":176,
  "chain_num":1,
  "ctime":1561701760,
  "hash":"5f4282775ebfaac7b07fbc060a4d4f25d83615f8d3ecc3847ccbbe891d7398d1",
  "hash_prev":"0000000000000000000000000000000000000000000000000000000000000000",
  "hhash":"b57e9bf37663e5a8c2c88bf48090b96774384e5c0a206efe3aecfb35765789b1",
  "hid":10,
  "id":1,
  "nonce":0,
  "payload_size":14,
  "root_block_body_hash":"474ecf5b105d10d9068d3f592742f3ee1bc58ecf36aa45f31926de1b865128eb",
  "script_hash":"0000000000000000000000000000000000000000000000000000000000000000",
  "version":"1.0.0"
}