Ensure DiskFileUpload#toString returns a string that uses the correct deleteOnExit (#11628)

Motivation:
DiskFileUpload#toString should use the value provided when constructing DiskFileUpload
and not the default one

Modification:
- DiskFileUpload#toString is modified to use the correct deleteOnExit value

Result:
DiskFileUpload#toString returns a string that uses the correct deleteOnExit

codec-http/src/main/java/io/netty/handler/codec/http/multipart/DiskFileUpload.java

@@ -138,8 +138,7 @@ public class DiskFileUpload extends AbstractDiskHttpData implements FileUpload {
                 HttpHeaderNames.CONTENT_LENGTH + ": " + length() + "\r\n" +
                 "Completed: " + isCompleted() +
                 "\r\nIsInMemory: " + isInMemory() + "\r\nRealFile: " +
-                (file != null ? file.getAbsolutePath() : "null") + " DefaultDeleteAfter: " +
-                deleteOnExitTemporaryFile;
+                (file != null ? file.getAbsolutePath() : "null") + " DeleteAfter: " + deleteOnExit;
     }
 
     @Override