Bug#938946: -t ignored with reinstall

[積丹尼 Dan Jacobson]

Yes, e.g., to convert to a 100% unstable system, one must resort to
outside tools (apt-show-versions),
# set $(apt-show-versions |grep /unknown | sed s!:.*!/unstable!) #or
# set $(apt-show-versions |grep 'newer than version in archive' | sed 
s!:.*!/unstable!)
# aptitude install $@
(Also wipes out which packages were marked as autoinstalled.)