Build with compat-lua-devel on f20+
    
    On <= f19 we need lua-devel and on >= f20 we need compat-lua-devel,
    tolua++-devel will automatically drag in the right one for us, so we
    can simply drop the lua-devel BuildRequires.
    
    Signed-off-by: Hans de Goede <hdegoede@redhat.com>