[shotwell] Fix leak while scrolling

[Jens Georg <jensgeorg src gnome org>]

commit 2d300134b66139f3dc18577bedf83266a3e0b13c
Author: Jens Georg <mail jensge org>
Date:   Sun Sep 18 20:02:34 2016 +0200

    Fix leak while scrolling
    
    Signed-off-by: Jens Georg <mail jensge org>

 src/core/DataObject.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/core/DataObject.vala b/src/core/DataObject.vala
index 4d4566e..3c98e9e 100644
--- a/src/core/DataObject.vala
+++ b/src/core/DataObject.vala
@@ -115,7 +115,7 @@ public abstract class DataObject : Object {
         return object_id;
     }
     
-    public Value? get_collection_property(string name, Value? def = null) {
+    public Value get_collection_property(string name, Value? def = null) {
         if (member_of == null)
             return def;