[gnome-software] Fix "void function should not return a value" error for clang

[Ting-Wei Lan <lantw src gnome org>]

commit e1c17f18c54dc7a3fbc3195cc7d260ca4ecf4d4a
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sun Jul 6 12:20:48 2014 +0800

    Fix "void function should not return a value" error for clang

 src/gs-shell.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-shell.c b/src/gs-shell.c
index ec45068..4395735 100644
--- a/src/gs-shell.c
+++ b/src/gs-shell.c
@@ -465,7 +465,7 @@ gs_shell_setup (GsShell *shell, GsPluginLoader *plugin_loader, GCancellable *can
        GsShellPrivate *priv = shell->priv;
        GtkWidget *widget;
 
-       g_return_val_if_fail (GS_IS_SHELL (shell), NULL);
+       g_return_if_fail (GS_IS_SHELL (shell));
 
        priv->plugin_loader = g_object_ref (plugin_loader);
        priv->cancellable = g_object_ref (cancellable);