[Tango-artists] Minor tweaks to small versions of dialog-warning

[Steven Garrity]

 From #tango:

(10:27:00) sgarrity: I've been using the warning icon, and I find the 
small versions (especially 16px) to be a bit dark. I've made some 
*really* minor changes - let me know what you think: 
http://actsofvolition.com/images/screenshots/tango/warning-brighter.png
(10:27:22) sgarrity: the 48px version is the same, 16px is a bit 
brighter, and 22px is a tiny bit brighter (hardly any change there though)
(10:27:57) andreasn: yeah, that looks cleaner

Here are the final versions:
http://actsofvolition.com/images/screenshots/tango/16x16/dialog-warning.png
http://actsofvolition.com/images/screenshots/tango/22x22/dialog-warning.png

The full size SVG remains unchanged.

Thanks,
Steven Garrity