ts2phc: Use proper close method on the error path.

When creating a ts2phc slave, a clock is obtained by invoking the
posix_clock_open() method.  However, in case of an error, the same clock
is closed again by calling close(2) on the associated file descriptor
directly.  While not incorrect, still the code should instead use the
close function that matches the open method.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

ts2phc_slave.c

@@ -223,7 +223,7 @@ no_ext_ts:
 no_pin_func:
 	servo_destroy(slave->servo);
 no_servo:
-	close(slave->fd);
+	posix_clock_close(slave->clk);
 no_posix_clock:
 	free(slave->name);
 	free(slave);