Switch from tf.contrib.metrics to tf.metrics (#18783)

* Switch from tf.contrib.metrics to tf.metrics

Much of the functions in `tf.contrib.metrics` has been
deprecated in favor of `tf.metrics`. This fix
switches `tf.contrib.metrics` to `tf.metrics`.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Change to `tf.metrics` in evaluation_test.py

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Fix pylint issue

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>