b52d647de2
Since our scripts were converted to Python, we can no longer
source them from a shell. Execute them directly instead. Also,
we now need to import configuration variables ourselves, since
scylla_prepare, being an independent process, won't do it for
us.
Fixes #3647
Message-Id: <20180802153017.11112-1-avi@scylladb.com>
(cherry picked from commit c9caaa8e6e)