[gnome-continuous] Drop appdata-tools

[Emmanuele Bassi <ebassi src gnome org>]

commit b57a1f1b1530a1ad4a2e48e8317ad04634f6ca8f
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Nov 27 14:01:55 2017 +0000

    Drop appdata-tools
    
    There's no such repository any more.

 manifest.json |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/manifest.json b/manifest.json
index a4c12e6..1df294e 100644
--- a/manifest.json
+++ b/manifest.json
@@ -955,8 +955,6 @@
                                  "--disable-man",
                                  "--disable-gtk-doc"]},
 
-                {"src": "git:https://github.com/hughsie/appdata-tools.git"},
-
                 {"src": "flatpak:flatpak",
                  "config-opts": ["--disable-documentation",
                                  "--enable-installed-tests"]},