API node crash

log:
```
2019-01-29T00:40:07  th_a:invoke get_item             get_item ] Couldn't find block 00dbdc3b0c85051ee00b37184000000000000000 -- corresponding ID in our chain is 00dbdc3b0c85051ee00b37185f8a62d54a4b191f                      application.cpp:643
```

refer to: https://github.com/steemit/steem/issues/1524