[gnome-control-center] printers: Check whether we have a device name

[Marek Kašík <mkasik src gnome org>]

commit b02f7722dd1a1ba921bc318660546d58757229c0
Author: Marek Kasik <mkasik redhat com>
Date:   Tue May 26 16:34:39 2015 +0200

    printers: Check whether we have a device name
    
    Check whether we've been able to find a usable name of given device
    to avoid dereference of NULL in canonicalize_device_name().
    
    https://bugzilla.gnome.org/show_bug.cgi?id=749896

 panels/printers/pp-utils.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/panels/printers/pp-utils.c b/panels/printers/pp-utils.c
index 85d68ab..ac2b9dd 100644
--- a/panels/printers/pp-utils.c
+++ b/panels/printers/pp-utils.c
@@ -4161,6 +4161,9 @@ canonicalize_device_name (GList         *devices,
       name = g_strdup (device->device_info);
     }
 
+  if (name == NULL)
+    return NULL;
+
   g_strstrip (name);
   g_strcanon (name, ALLOWED_CHARACTERS, '-');