[gnome-boxes] tests: use nonet for AppStream metadata test

[Felipe Borges <felipeborges src gnome org>]

commit c2f0f628ffb343f33272fee34401896b9736e47a
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Fri Feb 8 21:01:41 2019 -0500

    tests: use nonet for AppStream metadata test
    
    The build tests are often run on distro build machines
    that do not have outside Internet access so let's
    only use the AppStream validation tests that don't
    require Internet. This currently means that the
    screenshots are not checked.

 data/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/data/meson.build b/data/meson.build
index f770c918..460e17bb 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -81,7 +81,7 @@ if appstream_util.found()
   test(
     'validate-appdata', appstream_util,
     args: [
-      'validate-relax', appdata_file.full_path()
+      'validate-relax', '--nonet', appdata_file.full_path()
     ]
   )
 endif