Fix badge image conversion issues
Fix badge image conversion issues

This fixes the problem where if you try to create a badge with a PNG
image that has an alpha channel, django-badger takes that alpha channel
out back and shoots it in the face with fire changing it to charcoal
black.

mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org,mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org,deepankverma/badges.mozilla.org,mozilla/badges.mozilla.org,mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org