CLI: fix traceback due unavailable display

Tuna showing traceback when user haven't set DISPLAY variable and using CLI with param -l.
This is caused by gtk library which try create "window", but in CLI mode is not neccesary.
Patch remove unnecesary library which cause this problem

Tested-by: Jiri Kastner <jkastner@redhat.com>
Signed-off-by: Petr Oros <poros@redhat.com>
Signed-off-by: Jiri Kastner <jkastner@redhat.com>