Disk Quota Applet: Icon sizes

[Dominik Haumann]

Hi all,

the disk quota applet's icons are still too big, see
http://i.imgur.com/cBVPXuu.png

At Akademy 2015, I was asking some developers what do do about it,
but noone could give me hint.

Since these icons are *really* too big, I think we should do something about
it at least now.

Obviously the margin of these icons is wrong. Do I need to adapt the SVGs
somehow? All icons live in one svg file with different IDs.

Any hint would be very much appreciated!

Cheers,
Dominik