Use the static storage to check mimetype icon existence.
Review Request #3166 — Created June 29, 2012 and submitted
Use the static storage to check mimetype icon existence. Our mimetype icon existence code was assuming the existance of STATIC_ROOT and then looking for file existence from there. This isn't really how it should be used, and will fail when it's not even local storage or when it's a dev install. Now, we use the pipeline storage's exists() function, which will do the right thing. As part of this, I've cleaned up the path building a little bit.
Tested this with my local dev install without any static media collected. I previously was hitting the default fallback icon, but now I'm hitting the proper icons for the file attachments.