[SPARK-3124] [SQL] Fix the assembly jar conflict

Both netty-3.2.2.Final.jar and netty-3.6.6.Final.jar are flatten into the assembly package, however, the class(NioWorker) signature difference leads to the failure in launching sparksql CLI/ThriftServer.

This is a work around solution to ignore the netty-3.2.2.Final jar while doing the assembling with sbt.
There should not be modified.
We should modify the file `sql/hive-thriftserver/pom.xml`
```xml
    <dependency>
      <groupId>org.spark-project.hive</groupId>
      <artifactId>hive-cli</artifactId>
      <version>${hive.version}</version>
      <exclusions>
        <exclusion>
          <groupId>org.jboss.netty</groupId>
          <artifactId>netty</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
```