SeriesController: remove unused import.

Fixes PMD/CheckStyle warnings and unbreak building.

Should be in e0e22c5 commit.

Author: php-coder

src/main/java/ru/mystamps/web/controller/SeriesController.java

@@ -44,7 +44,6 @@
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.InitBinder;
-import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestParam;