installer: generate removed-files list so we can delete them on update
http://bugs.activestate.com/show_bug.cgi?id=100203

(integrated from komodo (trunk) change 81866 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13605 b87d16e7-d29f-4ee1-b5ec-817d645d335f