TFLearn Estimator Summary Writer Fix (#7555)

* Fix evaluation summary writing. TFLearn

* Update estimator.py

Fixed White Space

* Fix similar issue. 

Fix similar issue under, `tensorflow/python/estimators/estimator.py`

* Filter out "global_step"

This is seemingly the best way to ensure we don't write "global_step" to the summary, (which would be useless), while not modifying the dictionary. 

(Pull request for the other `estimator.py` incoming.)

* Filter "global_step" [part 2]

Same as other `estimator.py`.