MINOR: stconn/channel: Move CF_READ_DONTWAIT into the SC and rename it

The channel flag CF_READ_DONTWAIT is renamed to SC_FL_RCV_ONCE and moved
into the stream-connector.
diff --git a/src/http_ana.c b/src/http_ana.c
index bd2be1b..b8bad1e 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -1368,7 +1368,7 @@
 		}
 
 		channel_dont_close(rep);
-		rep->flags |= CF_READ_DONTWAIT; /* try to get back here ASAP */
+		s->scb->flags |= SC_FL_RCV_ONCE; /* try to get back here ASAP */
 		DBG_TRACE_DEVEL("waiting for more data",
 				STRM_EV_STRM_ANA|STRM_EV_HTTP_ANA, s, txn);
 		return 0;