[tracker/wip/jfelder/ontology-external-reference-identifier] ontologies: tracker:ExternalReference can have only one nie:identifier

[Jean Felder <jfelder src gnome org>]

commit 57562707b4c39a71afaf86381f9a3d3bcd211731
Author: Jean Felder <jfelder src gnome org>
Date:   Mon Sep 2 20:00:14 2019 +0200

    ontologies: tracker:ExternalReference can have only one nie:identifier

 src/ontologies/nepomuk/90-tracker.ontology | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/ontologies/nepomuk/90-tracker.ontology b/src/ontologies/nepomuk/90-tracker.ontology
index 7eaa7e09b..4b90b3ed4 100644
--- a/src/ontologies/nepomuk/90-tracker.ontology
+++ b/src/ontologies/nepomuk/90-tracker.ontology
@@ -78,7 +78,6 @@ tracker:referenceSource a rdf:Property ;
         rdfs:label "Source" ;
         rdfs:comment "Source of the external reference (eg. 'Musicbrainz')" ;
         nrl:maxCardinality 1 ;
-        rdfs:subPropertyOf nie:identifier ;
         rdfs:domain tracker:ExternalReference ;
         rdfs:range rdfs:Resource .