## What changes were proposed in this pull request?
It seems most of Python examples were changed to use SparkSession by https://github.com/apache/spark/pull/12809. This PR said both examples below:
- `simple_params_example.py`
- `aft_survival_regression.py`
are not changed because it dose not work. It seems `aft_survival_regression.py` is changed by https://github.com/apache/spark/pull/13050 but `simple_params_example.py` is not yet.
This PR corrects the example and make this use SparkSession.
In more detail, it seems `threshold` is replaced to `thresholds` here and there by 5a23213c14. However, when it calls `lr.fit(training, paramMap)` this overwrites the values. So, `threshold` was 5 and `thresholds` becomes 5.5 (by `1 / (1 + thresholds(0) / thresholds(1)`).
According to the comment below. this is not allowed, 354f8f11bd/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala (L58-L61).
So, in this PR, it sets the equivalent value so that this does not throw an exception.
## How was this patch tested?
Manully (`mvn package -DskipTests && spark-submit simple_params_example.py`)
Author: hyukjinkwon <gurwls223@gmail.com>
Closes#13135 from HyukjinKwon/SPARK-15031.
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