[gnome-software] trivial: Perhaps fix a hard to hit critical warning

[Richard Hughes <rhughes src gnome org>]

commit ee28be364e6c7d4f83ef87c45e90c1df8d8417fa
Author: Richard Hughes <richard hughsie com>
Date:   Thu Aug 7 16:54:10 2014 +0200

    trivial: Perhaps fix a hard to hit critical warning

 src/gs-shell-search-provider.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/gs-shell-search-provider.c b/src/gs-shell-search-provider.c
index 8d9f36d..1827b30 100644
--- a/src/gs-shell-search-provider.c
+++ b/src/gs-shell-search-provider.c
@@ -257,6 +257,8 @@ handle_get_result_metas (GsShellSearchProvider2        *skeleton,
        g_variant_builder_init (&builder, G_VARIANT_TYPE ("aa{sv}"));
        for (i = 0; results[i]; i++) {
                meta_variant = (GVariant*)g_hash_table_lookup (self->metas_cache, results[i]);
+               if (meta_variant == NULL)
+                       continue;
                g_variant_builder_add_value (&builder, meta_variant);
        }