[gnome-games/wip/exalm/flatpak] flatpak: Pin down DOSBox commit

[Alexander Mikhaylenko <alexm src gnome org>]

commit 77df68ef644481ef20728ea6dac3788eeb20edb4
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Mon Sep 3 09:55:03 2018 +0500

    flatpak: Pin down DOSBox commit
    
    The latest commit doesn't build, and a few commits before that don't
    install sofile.

 flatpak/libretro-cores/libretro-dosbox.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/flatpak/libretro-cores/libretro-dosbox.json b/flatpak/libretro-cores/libretro-dosbox.json
index 228f1de6..597ee2f3 100644
--- a/flatpak/libretro-cores/libretro-dosbox.json
+++ b/flatpak/libretro-cores/libretro-dosbox.json
@@ -19,7 +19,8 @@
             "sources": [
                 {
                     "type": "git",
-                    "url": "https://github.com/libretro/dosbox-libretro.git";
+                    "url": "https://github.com/libretro/dosbox-libretro.git";,
+                    "commit": "51b0deba703f1283420103f217d63edf8f5a6f5b"
                 },
                 {
                     "type": "file",