Add diskUsageThreshold to 0.99 (#5970)

### Motivation

The current GitHub action test will show that the disk space exceeds 95%, and then the bookie will detect that bookie exits, so fix this problem.

![image](https://user-images.githubusercontent.com/1907867/71616693-8748da00-2bf2-11ea-82f2-e54eda012136.png)


### Modifications

* Configuration parameter disUsageThreshold is 0.99 to prevent bookie exit.

### Verifying this change

Integration test pass
3 files changed
tree: dd3339cdc39bc7f6c4ef4812df97f5729c75df87
  1. distribution/
  2. docker/
  3. tests/