[nautilus] flatpak: Fix JSON manifest some more

[Ernestas Kulik <ernestask src gnome org>]

commit 3ae0c8901e22135b5c0186e6d82fd98acabffdd0
Author: Ernestas Kulik <ernestask gnome org>
Date:   Thu Dec 6 08:06:48 2018 +0000

    flatpak: Fix JSON manifest some more
    
    Booleans are not strings.

 build-aux/flatpak/org.gnome.Nautilus.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/build-aux/flatpak/org.gnome.Nautilus.json b/build-aux/flatpak/org.gnome.Nautilus.json
index 7883b4849..f8208c23d 100644
--- a/build-aux/flatpak/org.gnome.Nautilus.json
+++ b/build-aux/flatpak/org.gnome.Nautilus.json
@@ -66,7 +66,7 @@
                 "/libexec"
             ],
             "buildsystem": "meson",
-            "builddir": "true",
+            "builddir": true,
             "config-opts" : [
                 "--libdir=lib",
                 "-Ddocs=false",