After looking at the debian python policy (I don't grok python) this seems pretty obvlously caused by multiple bugs in calibre, namely that it creates the .pyc files on first start rather than in post-install (as per policy) and doesn't remove the files in the pre-remove script (as required by policy).
-- The choice of a Deliantra, the free code+content MORPG -----==- _GNU_ http://www.deliantra.net ----==-- _ generation ---==---(_)__ __ ____ __ Marc Lehmann --==---/ / _ \/ // /\ \/ / schm...@schmorp.de -=====/_/_//_/\_,_/ /_/\_\