Diff then patch fails on certain json

## Expected Behavior
If JsonDiff.asJson succeeds then JsonPatch.apply should succeed

## Actual Behavior
JsonPatch.apply fails with `[MOVE Operation] Missing field`

## Steps to Reproduce the Problem

```
ObjectMapper mapper = new ObjectMapper();
JsonNode source = mapper.readTree("{\"16\":[{\"id\":\"one\",\"type\":\"page\",\"length\":1}],\"63\":[{\"id\":\"two\",\"length\":2}],\"76\":[{\"id\":\"three\",\"length\":3}]}");
JsonNode target = mapper.readTree("{\"16\":[{\"id\":\"four\",\"length\":4}],\"76\":[{\"id\":\"five\",\"type\":\"page\",\"length\":5}]}");
JsonNode diff = JsonDiff.asJson(source, target);
JsonPatch.apply(diff, source);

[MOVE Operation] Missing field "77" at root
at com.flipkart.zjsonpatch.JsonPatch.process(JsonPatch.java:112)
at com.flipkart.zjsonpatch.JsonPatch.apply(JsonPatch.java:127)
at com.flipkart.zjsonpatch.JsonPatch.apply(JsonPatch.java:132)
```

## Specifications
The json looks contrived, but it is a real world example from comparing facebook posts.
Java 1.8, Jackson 2.9.9, zjsonpatch 0.4.9