MINOR: connection: move the cleanup of flag CO_FL_WAIT_ROOM

This flag is only used when reading using splicing for now, and is only
set when a pipe full condition is met, so we can simplify its reset
condition in conn_refresh_polling_flags so that it's cleared at the
same time as the other ones, only when the control layer is ready.

This flag could be used more, to mark that a buffer full condition was
met with any receive method in order to simplify polling management.
This should probably be revisited after 1.8.
diff --git a/include/proto/connection.h b/include/proto/connection.h
index 3fcba26..1cc2169 100644
--- a/include/proto/connection.h
+++ b/include/proto/connection.h
@@ -171,11 +171,10 @@
  */
 static inline void conn_refresh_polling_flags(struct connection *conn)
 {
-	conn->flags &= ~CO_FL_WAIT_ROOM;
-
 	if (conn_ctrl_ready(conn)) {
-		unsigned int flags = conn->flags & ~(CO_FL_CURR_RD_ENA | CO_FL_CURR_WR_ENA);
+		unsigned int flags = conn->flags;
 
+		flags &= ~(CO_FL_CURR_RD_ENA | CO_FL_CURR_WR_ENA | CO_FL_WAIT_ROOM);
 		if (fd_recv_active(conn->handle.fd))
 			flags |= CO_FL_CURR_RD_ENA;
 		if (fd_send_active(conn->handle.fd))