/series/import/request/{id}(quantity): add integration test for min value

[0pdd]

The puzzle 709-fd5f9ae4 (from #709) in src/main/java/ru/mystamps/web/controller/dto/ImportSeriesForm.java (lines 55-55) has to be resolved: "/series/import/request/{id}(quantity): add integration test for min value"

The puzzle was created by Slava Semushin on 24-Nov-17.

Tech debt for: 97e27e3 (#709)