Comment 3 for bug 1264611

 I tracked the problem to /var/lib/dpkg/info/nvidia-prime.postrm: 75 (just as the log says)

I have found a fix ( well, almost a fix ). I used "sudo leafpad" to open the "/var/lib/dpkg/info/nvidia-prime.postrm" file. I deleted everything between
          " # Restore the alternatives to a non prime
            # configuration, if possible
            os_release="$(lsb_release -c | cut -d: -f2 | sed "s/\t//g")" "
                  and
          "update-alternatives --auto "$other_arch" || true
                fi
            fi "
 I was now able to remove it using autoremove and reinstall. I don't know if this method is safe.