force split flag is used when a user requests region split and specifies a split key.
We need to clear force split flag at the end of SplitRequest run. If the region split is successful, this parent region will go away and there is no need to clear this flag. But we will have problem when the split is not successful or rejected. Here is the case:
1. User requested region split at rownkey-n.
2. We set forceSplit in the region with rownkey-n.
3. The split request got rejected because the region had references.
4. After a while, there was a system request split for the same region.
5. The region would use forceSplit and rownkey-n to split. What should have happened is that the region split is done based on system split policy.