[Libreoffice] Remove duplicate 'placeholder' icons

[Andrew C. E. Dent]

Hi Joachim 
Great you want to work on this:  http://wiki.documentfoundation.org/Development/Easy_Hacks#don.27t_ship_150_duplicate_placeholder_icons 
There is no need to create multiple sizes for this- defeats the point of being lean!We should just use a 16x16 image. The UI code seems to handle this ok.
I'm still working on an Icon Theme spec... icon suggested here:http://wiki.documentfoundation.org/Development/Icon_Themes/Status
Please note, this should have no impact on load performance! There is <4% of these missing icons, of which none should be referenced in the code anyway.
Cheers,Andrew