Fix translations not showing in the Sort by and Additional Information submenus

[Frank Reininghaus]

Hi Christoph,

2012/8/23 Christoph Feck:
> Hi Albert and Frank,
>
> Regarding the "(I18N_EMPTY_MESSAGE)" in Dolphin menus,
> the problem is indeed caused by above commit.
>
> The issue is that the code expects an empty string for the group
> header, if the actions should not be grouped in a sub-menu, but stay
> at top level.
>
> Attached patch fixes the issue for me, but I don't like the long line,
> so please improve :)

thanks, good catch! I'm actually OK with the long line, but maybe I'll
break it in two and add a comment to make sure that this issue doesn't
come back accidentally.

Best regards,
Frank