File dialog button text is missing
Created by: maksloboda
Godot version: 3.0
OS/device including version: ubuntu 17.10 (64 bit), windows 10(64 bit)
Issue description: After project export "Open" button on file dialogs is empty
Steps to reproduce: 1.Export minimal project 2.Run 3.Button is empty
Minimal project: filedialogbug.zip