fix(DBOjbect): Display attribute value in uniqueness rule message

[Hipska]

Base information

Question	Answer
Related to a SourceForge thread / Another PR / Combodo ticket?	N/A
Type of change?	Bug fix

Symptom

The generic uniqueness rule message for no_duplicate displays the field label twice:

Location: Test location is already linked to Role: Role, duplicates are not allowed on this relation.

Reproduction procedure

1. Add a new uniqueness_rules/rule with id no_duplicate in the class datamodel.
2. Try to create a duplicate who would match the rule.
3. Observe the error message as shown above.

Cause

The DBObject::GetUniquenessRuleGenericMessage method wrongly calls AttributeDefinition::GetLabel with the attribute value as parameter.

Proposed solution

Call AttributeDefinition::GetValueLabel instead.

I could not add a test for this case in UniquenessMessageTest, since (I think) there are no uniqueness rules without a custom message and without externalkey attributes in the standard datamodel.

Checklist before requesting a review

• I have performed a self-review of my code
• I have tested all changes I made on an iTop instance
• I have added a unit test, otherwise I have explained why I couldn't
• Is the PR clear and detailed enough so anyone can understand digging in the code?

[Hipska]

IMHO, this rule should have been named no_duplicate_relation, so regular duplicate rules like on Person could also use a generic message with no_duplicate. I see for Person the id name has been chosen instead.