[folks] core: Remove use of a deprecated libgee API

[Philip Withnall <pwithnall src gnome org>]

commit f78bee03297a2d886ba0a0535498d87d238bcf9f
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Thu Jan 22 16:18:39 2015 +0000

    core: Remove use of a deprecated libgee API

 folks/individual-aggregator.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/folks/individual-aggregator.vala b/folks/individual-aggregator.vala
index 3a3b7fd..3f10fba 100644
--- a/folks/individual-aggregator.vala
+++ b/folks/individual-aggregator.vala
@@ -553,7 +553,7 @@ public class Folks.IndividualAggregator : Object
             var store_full_id = this._get_store_full_id (
                 this._configured_primary_store_type_id,
                 this._configured_primary_store_id);
-            if (store_full_id in this._stores)
+            if (this._stores.has_key (store_full_id))
               {
                   var selected_store = this._stores.get (store_full_id);
                   this._set_primary_store (selected_store);