compatibility improvement for postgresql82-server

[apinstein@…]

For starting/stopping the server, you should do:

instead of

  su postgres -c "${PGCTL} -D ${POSTGRESQL82DATA:=/opt/local/var/db/postgresql82/defaultdb} start -l /opt/local/var/log/postgresql82/postgres.log"

do

  sudo -u $PGUSER sh -c "${DAEMON} -D '${PGDATA}' | ${LOGUTIL} '${PGLOG}' ${ROTATESEC} &"

The latter is the postgresql way now, and doesn't require the "postgres" user to have a login shell, which is more secure.

Also, when creating the "postgresql" user, set the shell to /usr/bin/false.