[gnome-software/wip/mcrha/uninitialized-variable] gs-upgrade-banner: Initialize a g_autofree variable

[Milan Crha <mcrha src gnome org>]

commit e7369c5ca2d29da8767ba96a42d855997ecf5000
Author: Milan Crha <mcrha redhat com>
Date:   Fri Oct 8 09:10:56 2021 +0200

    gs-upgrade-banner: Initialize a g_autofree variable
    
    Spotted in a build log.

 src/gs-upgrade-banner.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/gs-upgrade-banner.c b/src/gs-upgrade-banner.c
index 6026f4ad6..8baf484cc 100644
--- a/src/gs-upgrade-banner.c
+++ b/src/gs-upgrade-banner.c
@@ -132,7 +132,7 @@ gs_upgrade_banner_refresh (GsUpgradeBanner *self)
                gtk_label_set_markup (GTK_LABEL (priv->label_download_info), link);
        } else if (gs_app_get_size_download (priv->app) != GS_APP_SIZE_UNKNOWABLE &&
                   gs_app_get_size_download (priv->app) != 0) {
-               g_autofree gchar *tmp;
+               g_autofree gchar *tmp = NULL;
                g_clear_pointer (&str, g_free);
                tmp = g_format_size (gs_app_get_size_download (priv->app));
                /* Translators: the '%s' is replaced with the download size, forming text like "2 GB 
download" */