core: drop "argv" field from ExecParameter structure

We always initialize it from the same field in ExecCommand anyway, hence
there's no point in passing it separately to exec_spawn(), after all we
already pass the ExecCommand structure itself anyway.

No change in behaviour.

src/core/socket.c

@@ -1889,8 +1889,6 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
 
         unit_set_exec_params(UNIT(s), &exec_params);
 
-        exec_params.argv = c->argv;
-
         r = exec_spawn(UNIT(s),
                        c,
                        &s->exec_context,