[seahorse] common: Collection: Predicate cannot be a property.

[Niels De Graef <nielsdg src gnome org>]

commit 71f7bfa3cb25e7f88c2c6d4dffd59504c25e3457
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Wed Aug 15 09:38:56 2018 +0200

    common: Collection: Predicate cannot be a property.
    
    This fixes an annoying warning.

 common/collection.vala | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/common/collection.vala b/common/collection.vala
index f10fe1ea..862288fe 100644
--- a/common/collection.vala
+++ b/common/collection.vala
@@ -28,10 +28,8 @@ public class Seahorse.Collection : Gcr.Collection, GLib.Object {
      */
     public Gcr.Collection base_collection { get; construct set; }
 
-    /**
-     * Predicate for matching objects into this set.
-     */
-    public Predicate? predicate { get; private set; }
+    /* Predicate for matching objects into this set. */
+    private Predicate? predicate;
 
     public Collection.for_predicate (Gcr.Collection base_collection, Predicate? pred, DestroyNotify? 
destroy_func) {
         GLib.Object (base_collection: base_collection);