Comment 20 for bug 766412

you can edit the file /var/lib/dpkg/info/language-selector-common.postinst go to the line with this content :
kill $(pgrep -U root '^ls-dbus-backend$') 2>/dev/null
at the end add || true to get this line
kill $(pgrep -U root '^ls-dbus-backend$') 2>/dev/null || true

run apt-get upgrade again

This fix the problem for me