Fixing bug. The PolicyProperty could not be deleted

src/java/DmWebPortal/src/java/gov/anl/aps/dm/portal/model/entities/PolicyProperty.java

@@ -70,7 +70,7 @@ public class PolicyProperty extends CloneableEntity
     @JoinColumn(name = "policy_type_id", referencedColumnName = "id")
     @ManyToOne(optional = false)
     private PolicyType policyType;
-    @OneToMany(cascade = CascadeType.ALL)
+    @OneToMany(cascade = CascadeType.ALL, mappedBy = "policyProperty")
     private List<ExperimentPolicyPropertyValue> experimentPolicyPropertyValueList;
     @OneToMany(cascade = CascadeType.ALL, mappedBy = "policyProperty")
     private List<AllowedPolicyValue> allowedPolicyValueList;