[gnome-music] query: Show songs only once

[Marinus Schraal <mschraal src gnome org>]

commit 6b23edf1c298cca2ce6f499e4afac9d98ad68973
Author: Marinus Schraal <mschraal src gnome org>
Date:   Tue May 10 09:28:24 2016 +0200

    query: Show songs only once
    
    The all songs query could return the same song multiple times, alter the
    query to return a song only once.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766115

 gnomemusic/query.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gnomemusic/query.py b/gnomemusic/query.py
index ba7bc52..80518fe 100644
--- a/gnomemusic/query.py
+++ b/gnomemusic/query.py
@@ -194,7 +194,7 @@ class Query():
     @staticmethod
     def songs(where_clause):
         query = '''
-    SELECT
+    SELECT DISTINCT
         rdf:type(?song)
         tracker:id (?song) AS ?id
         ?url