box/session.cc: clean up includes

src/box/session.cc

@@ -35,7 +35,6 @@
 #include "assoc.h"
 #include "trigger.h"
 #include "random.h"
-#include <sys/socket.h>
 #include "user.h"
 
 static struct mh_i32ptr_t *session_registry;