[tracker] libtracker-data: Keep a weak reference on the Variable to the Context

[Carlos Garnacho <carlosg src gnome org>]

commit c2eddbd8dd5a2452b10446a0062411073e420d05
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Jan 17 18:57:33 2016 +0100

    libtracker-data: Keep a weak reference on the Variable to the Context
    
    Otherwise we fall into circular references, and leaks eventually.

 src/libtracker-data/tracker-sparql-query.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index e610757..1b0842f 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -83,7 +83,7 @@ namespace Tracker.Sparql {
                public string sql_expression { get; private set; }
                public VariableBinding binding;
                string sql_identifier;
-               public Context origin_context { get; private set; }
+               public weak Context origin_context { get; private set; }
 
                public Variable (string name, int index, Context context) {
                        this.name = name;