remove logo numbering

[dmcbride]

alliance logo numbering was only required to work around CDN caching issues. We aren't using a CDN any time soon, and, even if we do, the solution there will be to reduce the cache life of the images from 5 years to something that allows us to periodically update the images (7-30 days, I expect).

If we remove the numbering, it may be possible to have the server check for the file and return back the logo automatically instead of using db space for it. But at the very least, we won't need to have a manual admin action for a logo change even if we have one for the first-time logo addition.