[INLONG-61] minor update & fix some typos

[dockerzhang]

1.  RoundRobinPartitionRouter
change
  ```
if (roundPartition != null) {
if (roundPartition.getDelayTimeStamp() < System.currentTimeMillis())

{ return roundPartition; }

}
  ```
to
```
if (roundPartition != null && roundPartition.getDelayTimeStamp() < System.currentTimeMillis())

{ return roundPartition; }

```

2. DefaultBrokerRcvQltyStats
fix below typos:
```
brokerStatis -> brokerStats
lastPrinttime -> lastPrintTime
cachedLinkQualitys -> cachedLinkQualities
curStatisItemSet -> curStatsItemSet
  needHoldCout -> needHoldCount
```

JIRA link - [INLONG-61] created by technoboy