streaming: Do not print session_index in handle_session_prepared
streaming: Do not print session_index in handle_session_prepared

session_index is always 0. It will be removed soon.

raphaelsc/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,kjniemi/scylla,kjniemi/scylla,avikivity/scylla,duarten/scylla,raphaelsc/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,kjniemi/scylla,raphaelsc/scylla,avikivity/scylla