spice: use console index as display id

... instead of maintaining our own numbering.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

ui/spice-core.c

@@ -853,7 +853,6 @@ int qemu_spice_add_interface(SpiceBaseInstance *sin)
 }
 
 static GSList *spice_consoles;
-static int display_id;
 
 bool qemu_spice_have_display_interface(QemuConsole *con)
 {
@@ -868,7 +867,7 @@ int qemu_spice_add_display_interface(QXLInstance *qxlin, QemuConsole *con)
     if (g_slist_find(spice_consoles, con)) {
         return -1;
     }
-    qxlin->id = display_id++;
+    qxlin->id = qemu_console_get_index(con);
     spice_consoles = g_slist_append(spice_consoles, con);
     return qemu_spice_add_interface(&qxlin->base);
 }