MAGETWO-80916: Save region correctly to save sales address from admin #11234

 - Merge Pull Request #11234 from raumatbel/magento2:FR#StateNotDisplayedSalesAdminAddress
 - Merged commits:
   1. 23efa60
   2. 9e7d3f4
   3. 8038e91
   4. ee56c70
   5. 08ffd20
   6. f524e64
   7. 7d2cfcd
   8. 900b05f
   9. ab90b21
   10. d5cd66f

Author: Oleksii Korshenko