CLEANUP: stconn: rename cs_conn_*() to sc_conn_*()

The following functions which act on a connection-based stream connector
were renamed to sc_conn_* (~60 places):

  cs_conn_drain_and_shut
  cs_conn_process
  cs_conn_read0
  cs_conn_ready
  cs_conn_recv
  cs_conn_send
  cs_conn_shut
  cs_conn_shutr
  cs_conn_shutw
8 files changed