[gnome-software] Don't crash when the moduleset data is not yet installed

[Richard Hughes <rhughes src gnome org>]

commit 201810074dd46eafd88d2dbd01c94a9d6e59a737
Author: Richard Hughes <richard hughsie com>
Date:   Fri Oct 10 16:06:16 2014 +0100

    Don't crash when the moduleset data is not yet installed
    
    This happens if you've done 'make install' in src/ but not in data/...

 src/plugins/gs-plugin-moduleset.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)
---
diff --git a/src/plugins/gs-plugin-moduleset.c b/src/plugins/gs-plugin-moduleset.c
index 2b9581c..014518c 100644
--- a/src/plugins/gs-plugin-moduleset.c
+++ b/src/plugins/gs-plugin-moduleset.c
@@ -127,6 +127,14 @@ gs_plugin_add_popular (GsPlugin *plugin,
                                                 "popular",
                                                 category);
        }
+       if (apps == NULL) {
+               ret = FALSE;
+               g_set_error (error,
+                            GS_PLUGIN_ERROR,
+                            GS_PLUGIN_ERROR_FAILED,
+                            "No moduleset data found");
+               goto out;
+       }
 
        /* just add all */
        for (i = 0; apps[i]; i++) {
@@ -179,6 +187,14 @@ gs_plugin_refine (GsPlugin *plugin,
                        }
                }
        }
+       if (apps == NULL) {
+               ret = FALSE;
+               g_set_error (error,
+                            GS_PLUGIN_ERROR,
+                            GS_PLUGIN_ERROR_FAILED,
+                            "No moduleset data found");
+               goto out;
+       }
 
        /* just mark each one as core */
        pkgs = gs_moduleset_get_modules (plugin->priv->moduleset,