[gnome-software] trivial: Make gs_app_notify_failed_modal() less asserty

[Richard Hughes <rhughes src gnome org>]

commit a484dec2fdfa357396b2e1a25267841b4d4c2fea
Author: Richard Hughes <richard hughsie com>
Date:   Thu Sep 8 13:33:11 2016 +0100

    trivial: Make gs_app_notify_failed_modal() less asserty

 src/gs-common.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-common.c b/src/gs-common.c
index 4cc2914..2d45ca3 100644
--- a/src/gs-common.c
+++ b/src/gs-common.c
@@ -183,9 +183,10 @@ gs_app_notify_failed_modal (GsApp *app,
                break;
        }
        default:
-               g_assert_not_reached ();
                break;
        }
+       if (msg->len == 0)
+               return;
        g_string_append (msg, " ");
 
        /* give details about the error */