Fix same issue from branch Master issue #291 for branch 3

src/main/java/org/jboss/netty/handler/codec/http/MixedAttribute.java

@@ -64,7 +64,7 @@ public class MixedAttribute implements Attribute {
                         .getName());
                 if (((MemoryAttribute) attribute).getChannelBuffer() != null) {
                     diskAttribute.addContent(((MemoryAttribute) attribute)
-                        .getChannelBuffer(), last);
+                        .getChannelBuffer(), true);
                 }
                 attribute = diskAttribute;
             }