I reproduced the crash on the -lts-saucy stack, confirmed that the fixed version works. And that installing the lts-trusty stack removes the broken kde-config-touchpad, the upgraded kde-config-touchpad installs correctly and doesn't crash.
I reproduced the crash on the -lts-saucy stack, confirmed that the fixed version works. And that installing the lts-trusty stack removes the broken kde-config- touchpad, the upgraded kde-config-touchpad installs correctly and doesn't crash.