Add default block in AbstractDnsMessage (#11327)

Motivation:

Every switch block should also have a default case.

Modification:

Add default block in AbstractDnsMessage to ensure we not fall-through by mistake

Result:

Cleanup

Signed-off-by: xingrufei <xingrufei@sogou-inc.com>

codec-dns/src/main/java/io/netty/handler/codec/dns/AbstractDnsMessage.java

@@ -427,6 +427,8 @@ public abstract class AbstractDnsMessage extends AbstractReferenceCounted implem
             return authorities;
         case 3:
             return additionals;
+        default:
+            break;
         }
 
         throw new Error(); // Should never reach here.
@@ -446,6 +448,8 @@ public abstract class AbstractDnsMessage extends AbstractReferenceCounted implem
         case 3:
             additionals = value;
             return;
+        default:
+            break;
         }
 
         throw new Error(); // Should never reach here.