Revert unintended change to TrafficLand logo on Friends page

In f77314a, "Optimize images", which changed many of the images on the
Friends page, the SVG markup was altered to give the TrafficLand logo a
blue background, which could not have been intended. Because the logo
was the same size before and after this commit (13 kb), and I cannot
otherwise imagine what was supposed to be optimized, simply revert the
change for that one file alone.

Author: bstrie