Fix progress reader output on close

Currently the progress reader won't close properly by not setting the close size.

fixes #11849

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
(cherry picked from commit aa3083f577224ad74384f648b17c1474ab47b44f)

Docker-DCO-1.1-Signed-off-by: Jessie Frazelle <jess@docker.com> (github: jfrazelle)

Docker-DCO-1.1-Signed-off-by: Jessie Frazelle <princess@docker.com> (github: jfrazelle)

pkg/progressreader/progressreader.go

@@ -64,6 +64,7 @@ func (config *Config) Read(p []byte) (n int, err error) {
 	return read, err
 }
 func (config *Config) Close() error {
+	config.Current = config.Size
 	config.Out.Write(config.Formatter.FormatProg(config.ID, config.Action, &JSONProg{Current: config.Current, Total: config.Size}))
 	return config.In.Close()
 }