[devhelp] flatpak: update TODO comment

[Sébastien Wilmet <swilmet src gnome org>]

commit 3dd03c730bb618079e3853357818a27f155af507
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Fri Jan 12 21:34:24 2018 +0100

    flatpak: update TODO comment

 flatpak/README |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/flatpak/README b/flatpak/README
index 00e80cd..814a21c 100644
--- a/flatpak/README
+++ b/flatpak/README
@@ -3,5 +3,5 @@ Flatpak for Devhelp
 
 Scripts are provided to test easily the Flatpak manifest.
 
-TODO:
-https://bugzilla.gnome.org/show_bug.cgi?id=792068
+TODO, longer-term, remove "--filesystem=host:ro" from the finish-args:
+https://bugzilla.gnome.org/show_bug.cgi?id=792068#c3