HADOOP-15264. AWS "shaded" SDK 1.271 is pulling in netty 4.1.17.

Contributed by Steve Loughran.

hadoop-project/pom.xml

@@ -829,6 +829,12 @@
         <groupId>com.amazonaws</groupId>
         <artifactId>aws-java-sdk-bundle</artifactId>
         <version>${aws-java-sdk.version}</version>
+        <exclusions>
+          <exclusion>
+            <groupId>io.netty</groupId>
+            <artifactId>*</artifactId>
+          </exclusion>
+        </exclusions>
       </dependency>
       <dependency>
         <groupId>org.apache.mina</groupId>