MINOR: connection: unconst mux's get_fist_cs() callback function

This change is mandatory for next commits.

include/haproxy/conn_stream.h

@@ -235,7 +235,7 @@ static inline void cs_set_error(struct conn_stream *cs)
  * conn_stream, NULL is returned. The output pointer is purposely marked
  * const to discourage the caller from modifying anything there.
  */
-static inline const struct conn_stream *cs_conn_get_first(const struct connection *conn)
+static inline struct conn_stream *cs_conn_get_first(const struct connection *conn)
 {
 	BUG_ON(!conn || !conn->mux);
 

include/haproxy/connection-t.h

@@ -396,7 +396,7 @@ struct mux_ops {
 	void (*shutw)(struct conn_stream *cs, enum co_shw_mode);     /* shutw function */
 
 	int (*attach)(struct connection *conn, struct conn_stream *, struct session *sess); /* attach a conn_stream to an outgoing connection */
-	const struct conn_stream *(*get_first_cs)(const struct connection *); /* retrieves any valid conn_stream from this connection */
+	struct conn_stream *(*get_first_cs)(const struct connection *); /* retrieves any valid conn_stream from this connection */
 	void (*detach)(struct conn_stream *); /* Detach a conn_stream from an outgoing connection, when the request is done */
 	int (*show_fd)(struct buffer *, struct connection *); /* append some data about connection into chunk for "show fd"; returns non-zero if suspicious */
 	int (*subscribe)(struct conn_stream *cs, int event_type,  struct wait_event *es); /* Subscribe <es> to events, such as "being able to send" */

src/mux_fcgi.c

@@ -3552,7 +3552,7 @@ static int fcgi_attach(struct connection *conn, struct conn_stream *cs, struct s
  * beneficial to scan backwards from the end to reduce the likeliness to find
  * orphans.
  */
-static const struct conn_stream *fcgi_get_first_cs(const struct connection *conn)
+static struct conn_stream *fcgi_get_first_cs(const struct connection *conn)
 {
 	struct fcgi_conn *fconn = conn->ctx;
 	struct fcgi_strm *fstrm;

src/mux_h1.c

@@ -3320,7 +3320,7 @@ static int h1_attach(struct connection *conn, struct conn_stream *cs, struct ses
 /* Retrieves a valid conn_stream from this connection, or returns NULL. For
  * this mux, it's easy as we can only store a single conn_stream.
  */
-static const struct conn_stream *h1_get_first_cs(const struct connection *conn)
+static struct conn_stream *h1_get_first_cs(const struct connection *conn)
 {
 	struct h1c *h1c = conn->ctx;
 	struct h1s *h1s = h1c->h1s;

src/mux_h2.c

@@ -4299,7 +4299,7 @@ static int h2_attach(struct connection *conn, struct conn_stream *cs, struct ses
  * beneficial to scan backwards from the end to reduce the likeliness to find
  * orphans.
  */
-static const struct conn_stream *h2_get_first_cs(const struct connection *conn)
+static struct conn_stream *h2_get_first_cs(const struct connection *conn)
 {
 	struct h2c *h2c = conn->ctx;
 	struct h2s *h2s;

src/mux_pt.c

@@ -399,7 +399,7 @@ static int mux_pt_attach(struct connection *conn, struct conn_stream *cs, struct
 /* Retrieves a valid conn_stream from this connection, or returns NULL. For
  * this mux, it's easy as we can only store a single conn_stream.
  */
-static const struct conn_stream *mux_pt_get_first_cs(const struct connection *conn)
+static struct conn_stream *mux_pt_get_first_cs(const struct connection *conn)
 {
 	struct mux_pt_ctx *ctx = conn->ctx;