[gnome-software] Do not crash if there is no /usr/share/appdata directory

[Richard Hughes <rhughes src gnome org>]

commit 83c3904977d40c879fb92bbf653d9a57aa23c812
Author: Richard Hughes <richard hughsie com>
Date:   Fri Oct 11 10:24:50 2013 +0100

    Do not crash if there is no /usr/share/appdata directory
    
    This can happen if no applications with AppData are installed on the system, and
    gnome-software is run locally.

 src/gs-plugin-loader.c          |    6 ++++++
 src/plugins/gs-plugin-appdata.c |   11 ++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)
---
diff --git a/src/gs-plugin-loader.c b/src/gs-plugin-loader.c
index 8166e3e..35c6a21 100644
--- a/src/gs-plugin-loader.c
+++ b/src/gs-plugin-loader.c
@@ -201,6 +201,12 @@ gs_plugin_loader_run_refine (GsPluginLoader *plugin_loader,
                ret = plugin_func (plugin, list, flags, cancellable, error);
                if (!ret)
                        goto out;
+               if (error != NULL && *error != NULL) {
+                       ret = FALSE;
+                       g_warning ("%s set %s but did not return FALSE!",
+                                  plugin->name, (*error)->message);
+                       goto out;
+               }
                gs_plugin_status_update (plugin, NULL, GS_PLUGIN_STATUS_FINISHED);
                gs_profile_stop (plugin_loader->priv->profile, profile_id);
                g_free (profile_id);
diff --git a/src/plugins/gs-plugin-appdata.c b/src/plugins/gs-plugin-appdata.c
index 19d4441..eb7487e 100644
--- a/src/plugins/gs-plugin-appdata.c
+++ b/src/plugins/gs-plugin-appdata.c
@@ -80,16 +80,21 @@ gs_plugin_destroy (GsPlugin *plugin)
 static gboolean
 gs_plugin_startup (GsPlugin *plugin, GError **error)
 {
-       gboolean ret = TRUE;
        GDir *dir;
+       GError *error_local = NULL;
        const gchar *tmp;
+       gboolean ret = TRUE;
        gchar *ext_tmp;
        gchar *id;
 
        /* find all the files installed */
-       dir = g_dir_open (plugin->priv->cachedir, 0, error);
-       if (dir == NULL)
+       dir = g_dir_open (plugin->priv->cachedir, 0, &error_local);
+       if (dir == NULL) {
+               g_debug ("Could not open AppData directory: %s",
+                        error_local->message);
+               g_error_free (error_local);
                goto out;
+       }
        while ((tmp = g_dir_read_name (dir)) != NULL) {
                if (g_strcmp0 (tmp, "schema") == 0)
                        continue;