remove files owned by the old user 'icecream' from /var/cache/icecream
    
    Commit 575176a72859 ("Update to proper user") changed the user name from
    'icecream' to 'icecc'. This seems completely pointless to me, but whatever.
    We must delete leftover files owned by 'icecream' from under
    /var/cache/icecream, because otherwise iceccd will attempt to do it by
    itself and fail.