Bug#513739: /var/cache/pbuilder not empty so not removed upon purge

[jidanni at jidanni.org]

>> dpkg - warning: while removing pbuilder, directory `/var/cache/pbuilder' not empty so not remo
JU> BTW, cannot reproduce in the case of installing / purging.
JU> You need to have done something before this happens, right ?
# aptitude install pbuilder
# pbuilder create
^C
# aptitude purge pbuilder

If you don't want to remove user data, then perhaps print a message
about it when detected. Otherwise it just looks like an unexpected
error.