Add missing @param annotations to CityRepository in Data REST sample

Without the @param annotations, using either of the search URIs would
resulted in a 400 response and an error describing the lack of @param
annotation.

See gh-1627

Author: ivan-yin

spring-boot-samples/spring-boot-sample-data-rest/src/main/java/sample/data/jpa/service/CityRepository.java

@@ -19,16 +19,19 @@
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.repository.PagingAndSortingRepository;
+import org.springframework.data.repository.query.Param;
 import org.springframework.data.rest.core.annotation.RepositoryRestResource;
 
 import sample.data.jpa.domain.City;
 
 @RepositoryRestResource(collectionResourceRel = "citys", path = "cities")
 interface CityRepository extends PagingAndSortingRepository<City, Long> {
 
-	Page<City> findByNameContainingAndCountryContainingAllIgnoringCase(String name,
-			String country, Pageable pageable);
+	Page<City> findByNameContainingAndCountryContainingAllIgnoringCase(
+			@Param("name") String name, @Param("country") String country,
+			Pageable pageable);
 
-	City findByNameAndCountryAllIgnoringCase(String name, String country);
+	City findByNameAndCountryAllIgnoringCase(@Param("name") String name,
+			@Param("country") String country);
 
 }