spark git commit: [SPARK-15084][PYTHON][SQL] Use builder pattern to create SparkSession in PySpark.

Repository: spark Updated Branches: refs/heads/branch-2.0 4c7f5a74d -> 5e15615d1 [SPARK-15084][PYTHON][SQL] Use builder pattern to create SparkSession in PySpark. ## What changes were proposed in this pull request? This is a python port of corresponding Scala builder pattern code. `sql.py`

spark git commit: [SPARK-15084][PYTHON][SQL] Use builder pattern to create SparkSession in PySpark.

Repository: spark Updated Branches: refs/heads/master c1839c991 -> 0903a185c [SPARK-15084][PYTHON][SQL] Use builder pattern to create SparkSession in PySpark. ## What changes were proposed in this pull request? This is a python port of corresponding Scala builder pattern code. `sql.py` is