Fixing mistake in Tracker_artifact tests
Merge remote-tracking branch 'stable/master' into 2005_SOAP_get_artifact_cross_references
Merge remote-tracking branch 'origin/2005_SOAP_get_artifact_cross_references' into tuleap-stable-master

* origin/2005_SOAP_get_artifact_cross_references:
  Fixing mistake in Tracker_artifact tests