[gdm] local-display-factory: don't assume display has display number

[Ray Strode <halfline src gnome org>]

commit 2ba0912414735ed38093d109b426b93bee88e99e
Author: Ray Strode <rstrode redhat com>
Date:   Mon Feb 16 12:48:07 2015 -0500

    local-display-factory: don't assume display has display number
    
    logind managed displays don't have (known) display numbers, so
    we shouldn't assert that there's going to be one on display
    status changes.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=744764

 daemon/gdm-local-display-factory.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/daemon/gdm-local-display-factory.c b/daemon/gdm-local-display-factory.c
index d49bf25..de2feb7 100644
--- a/daemon/gdm-local-display-factory.c
+++ b/daemon/gdm-local-display-factory.c
@@ -271,7 +271,6 @@ on_display_status_changed (GdmDisplay             *display,
 
         num = -1;
         gdm_display_get_x11_display_number (display, &num, NULL);
-        g_assert (num != -1);
 
         store = gdm_display_factory_get_display_store (GDM_DISPLAY_FACTORY (factory));
 
@@ -285,7 +284,9 @@ on_display_status_changed (GdmDisplay             *display,
         case GDM_DISPLAY_FINISHED:
                 /* remove the display number from factory->priv->used_display_numbers
                    so that it may be reused */
-                g_hash_table_remove (factory->priv->used_display_numbers, GUINT_TO_POINTER (num));
+                if (num != -1) {
+                        g_hash_table_remove (factory->priv->used_display_numbers, GUINT_TO_POINTER (num));
+                }
                 gdm_display_store_remove (store, display);
 
                 /* Create a new equivalent display if it was static */