HADOOP-16982. Update Netty to 4.1.48.Final. Contributed by Lisheng Sun.

Signed-off-by: Masatake Iwasaki <iwasakims@apache.org>

hadoop-project/pom.xml

@@ -140,7 +140,7 @@
     <htrace4.version>4.1.0-incubating</htrace4.version>
     <metrics.version>3.2.4</metrics.version>
     <netty3.version>3.10.6.Final</netty3.version>
-    <netty4.version>4.1.45.Final</netty4.version>
+    <netty4.version>4.1.48.Final</netty4.version>
 
     <!-- Maven protoc compiler -->
     <protobuf-maven-plugin.version>0.5.1</protobuf-maven-plugin.version>
@@ -1305,6 +1305,18 @@
             <groupId>jline</groupId>
             <artifactId>jline</artifactId>
           </exclusion>
+          <exclusion>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-all</artifactId>
+          </exclusion>
+          <exclusion>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-handler</artifactId>
+          </exclusion>
+          <exclusion>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-transport-native-epoll</artifactId>
+          </exclusion>
         </exclusions>
       </dependency>
       <dependency>