allow user to use the `supervisorctl' program to start and stop services. `exec` needed to be added to the scylla and scylla-jmx starter scripts - otherwise supervisord loses track of the actual process we want to manage. Signed-off-by: Yoav Kleinberger <yoav@scylladb.com> Message-Id: <1471442960-110914-1-git-send-email-yoav@scylladb.com>