services/content: ignore io.EOF after successful commit

Signed-off-by: Stephen J Day <stephen.day@docker.com>

services/content/service.go

@@ -310,6 +310,10 @@ func (s *Service) Write(session api.Content_WriteServer) (err error) {
 
 		req, err = session.Recv()
 		if err != nil {
+			if err == io.EOF {
+				return nil
+			}
+
 			return err
 		}
 	}