Fix delete every nth

src/main/java/de/scads/privacy/privateroutes/measurement/Measurement.java

@@ -5,8 +5,6 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 import lombok.ToString;
-import org.hibernate.annotations.OnDelete;
-import org.hibernate.annotations.OnDeleteAction;
 
 import javax.persistence.*;