appveyor: disable workaround to compile git.1.9.0
appveyor: disable workaround to compile git.1.9.0

https://github.com/fdopen/opam-repository-mingw/ now contains latest
release of ocaml-git.

Signed-off-by: Thomas Gazagnaire <5f50a84c1fa3bcff146405017f36aec1a10a9e38@gazagnaire.org>

docker/datakit,docker/datakit,docker/datakit