[tracker] libtracker-direct: Fix compiler warning

[Carlos Garnacho <carlosg src gnome org>]

commit 097354737f1427f23ef6f52956b26ee76ac89a3c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Aug 31 22:39:59 2017 +0200

    libtracker-direct: Fix compiler warning
    
    Handle GLib.Error on async queries.

 src/libtracker-direct/tracker-direct.vala |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/libtracker-direct/tracker-direct.vala b/src/libtracker-direct/tracker-direct.vala
index e079e6e..06c6523 100644
--- a/src/libtracker-direct/tracker-direct.vala
+++ b/src/libtracker-direct/tracker-direct.vala
@@ -252,6 +252,7 @@ public class Tracker.Direct.Connection : Tracker.Sparql.Connection, AsyncInitabl
                Sparql.Error sparql_error = null;
                IOError io_error = null;
                DBusError dbus_error = null;
+               GLib.Error error = null;
                Sparql.Cursor result = null;
                var context = MainContext.get_thread_default ();
 
@@ -264,6 +265,8 @@ public class Tracker.Direct.Connection : Tracker.Sparql.Connection, AsyncInitabl
                                sparql_error = e_spql;
                        } catch (DBusError e_dbus) {
                                dbus_error = e_dbus;
+                       } catch (GLib.Error e) {
+                               error = e;
                        }
 
                        context.invoke (() => {