piuparts.conf.sample: explain default location of the file
Install cron files for piupartsm and piupartss users in /usr/share/doc/piuparts-(master|slave)/examples/. (Closes: #746721)
Install piuparts.conf.sample in /usr/share/doc/piuparts-master/examples/.
Install slave_run and slave_join in /usr/bin/ (Closes: #746718)