msi: Depend on mingw-adwaita-icon-theme
    
    Instead of maintain a file which includes every single icon that we use
    from adwaita-icon-theme (adwaita-icons-needed.wxi.in), let's depend on
    mingw-adwaita-icon-theme directly.
    It reduces considerably the maintainability and the risk to have missing
    icons. Although, the size of the final binary gets increased from ~35MB
    to ~50MB.
    
    Resolves: rhbz#1301064
    Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>
    Acked-by: Christophe Fergeau <cfergeau@redhat.com>