[gnome-software] extras: Fix two -Wmaybe-uninitialized warnings

[Kalev Lember <klember src gnome org>]

commit eb66bf0b60e47f29aca9d635291c3eee24d7ab55
Author: Kalev Lember <kalevlember gmail com>
Date:   Mon Mar 2 21:53:21 2015 +0100

    extras: Fix two -Wmaybe-uninitialized warnings

 src/gs-shell-extras.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/gs-shell-extras.c b/src/gs-shell-extras.c
index 349a788..bebcdce 100644
--- a/src/gs-shell-extras.c
+++ b/src/gs-shell-extras.c
@@ -422,7 +422,7 @@ build_no_results_label (GsShellExtras *shell_extras)
 {
        GsShellExtrasPrivate *priv = shell_extras->priv;
        GList *l;
-       GsApp *app;
+       GsApp *app = NULL;
        guint num;
        _cleanup_free_ gchar *codec_titles = NULL;
        _cleanup_free_ gchar *url = NULL;
@@ -1020,7 +1020,7 @@ row_activated_cb (GtkListBox *list_box,
 static gchar *
 get_app_sort_key (GsApp *app)
 {
-       _cleanup_string_free_ GString *key;
+       _cleanup_string_free_ GString *key = NULL;
 
        key = g_string_sized_new (64);