[gdm] Omit version in login window for unknown distros

[Ray Strode <halfline src gnome org>]

commit c04ba8e09110c72aeb9b3b1574bfd733cc661437
Author: Guido Trentalancia <guido trentalancia com>
Date:   Wed Sep 29 19:10:59 2010 -0400

    Omit version in login window for unknown distros

 gui/simple-greeter/gdm-greeter-login-window.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/gui/simple-greeter/gdm-greeter-login-window.c b/gui/simple-greeter/gdm-greeter-login-window.c
index cd9a162..ca170a5 100644
--- a/gui/simple-greeter/gdm-greeter-login-window.c
+++ b/gui/simple-greeter/gdm-greeter-login-window.c
@@ -1136,6 +1136,14 @@ get_system_version (void)
                         version = g_strdup (output);
                 }
                 version = g_strstrip (version);
+
+                /* lsb_release returns (none) if it doesn't know,
+                 * so return NULL in that case */
+                if (strcmp (version, "(none)") == 0) {
+                        g_free (version);
+                        version = NULL;
+                }
+
                 g_free (output);
 
                 goto out;