[SPARK-18972][CORE] Fix the netty thread names for RPC

## What changes were proposed in this pull request?

Right now the name of threads created by Netty for Spark RPC are `shuffle-client-**` and `shuffle-server-**`. It's pretty confusing.

This PR just uses the module name in TransportConf to set the thread name. In addition, it also includes the following minor fixes:

- TransportChannelHandler.channelActive and channelInactive should call the corresponding super methods.
- Make ShuffleBlockFetcherIterator throw NoSuchElementException if it has no more elements. Otherwise,  if the caller calls `next` without `hasNext`, it will just hang.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16380 from zsxwing/SPARK-18972.