Drop unneeded dependencies

After narrowing the functionality of ade tool to only manage sysroots the
dependencies were not re evaluated, causing several packages to be required
which are not really needed.

To avoid this problem, remove unneeded dependencies.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

debian/control

@@ -4,10 +4,8 @@ Section: devel
 Priority: optional
 Build-Depends: debhelper-compat (= 13),
                dh-sequence-python3,
-               flatpak,
                git-buildpackage,
                gnupg2,
-               ostree,
                python3-argcomplete,
                python3-debian,
                python3-gi,
@@ -22,7 +20,6 @@ Architecture: all
 Depends: abi-compliance-checker,
          devscripts,
          dpkg-dev,
-         flatpak,
          git-buildpackage,
          gitlab-rulez,
          libconfig-model-dpkg-perl,