machined: don't bother explicitly closing the errno pipe

There's no point in explicitly closing the errno pipe, if we exit right after
anyway. It doesn't hurt doing this either, but let's do this the same way for
all cases where we use the "Operation" object right now, and in all other cases
we do not close the pipe explicitly, hence don't do so here either.

src/machine/machine-dbus.c

@@ -1200,8 +1200,6 @@ int bus_machine_method_copy(sd_bus_message *message, void *userdata, sd_bus_erro
 
         child_fail:
                 (void) write(errno_pipe_fd[1], &r, sizeof(r));
-                errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
-
                 _exit(EXIT_FAILURE);
         }