Fix in addContent when switching from MemoryAttribute if it is done when last buffer added, in order to not close immediately the underlying file before adding the last buffer.

codec-http/src/main/java/io/netty/handler/codec/http/MixedAttribute.java

@@ -65,7 +65,7 @@ public class MixedAttribute implements Attribute {
                         .getName());
                 if (((MemoryAttribute) attribute).getChannelBuffer() != null) {
                     diskAttribute.addContent(((MemoryAttribute) attribute)
-                        .getChannelBuffer(), last);
+                        .getChannelBuffer(), false);
                 }
                 attribute = diskAttribute;
             }