CLEANUP: stconn: rename final state manipulation functions from cs_* to sc_*

This applies the following renaming. It's a bit large but pretty
mechanical:

cs_state -> sc_state  (enum)

cs_alloc_ibuf() -> sc_alloc_ibuf()
cs_is_conn_error() -> sc_is_conn_error()
cs_opposite() -> sc_opposite()
cs_report_error() -> sc_report_error()
cs_set_state() -> sc_set_state()
cs_state_bit() -> sc_state_bit()
cs_state_in() -> sc_state_in()
cs_state_str() -> sc_state_str()
diff --git a/src/cli.c b/src/cli.c
index d5e2d88..aeba3f3 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -1971,7 +1971,7 @@
 	struct cmsghdr *cmsg;
 	struct stconn *cs = appctx_cs(appctx);
 	struct stream *s = __sc_strm(cs);
-	struct connection *remote = sc_conn(cs_opposite(cs));
+	struct connection *remote = sc_conn(sc_opposite(cs));
 	struct msghdr msghdr;
 	struct iovec iov;
 	struct timeval tv = { .tv_sec = 1, .tv_usec = 0 };
@@ -2780,7 +2780,7 @@
 
 		sockaddr_free(&s->scb->dst);
 
-		cs_set_state(s->scb, SC_ST_INI);
+		sc_set_state(s->scb, SC_ST_INI);
 		s->scb->flags &= SC_FL_ISBACK | SC_FL_DONT_WAKE; /* we're in the context of process_stream */
 		s->req.flags &= ~(CF_SHUTW|CF_SHUTW_NOW|CF_AUTO_CONNECT|CF_WRITE_ERROR|CF_STREAMER|CF_STREAMER_FAST|CF_NEVER_WAIT|CF_WROTE_DATA);
 		s->res.flags &= ~(CF_SHUTR|CF_SHUTR_NOW|CF_READ_ATTACHED|CF_READ_ERROR|CF_READ_NOEXP|CF_STREAMER|CF_STREAMER_FAST|CF_WRITE_PARTIAL|CF_NEVER_WAIT|CF_WROTE_DATA|CF_READ_NULL);