spark git commit: [SPARK-22554][PYTHON] Add a config to control if PySpark should use daemon or not for workers

Repository: spark Updated Branches: refs/heads/master b10837ab1 -> 57c5514de [SPARK-22554][PYTHON] Add a config to control if PySpark should use daemon or not for workers ## What changes were proposed in this pull request? This PR proposes to add a flag to control if PySpark should use

spark git commit: [SPARK-22557][TEST] Use ThreadSignaler explicitly

Repository: spark Updated Branches: refs/heads/master d54bfec2e -> b10837ab1 [SPARK-22557][TEST] Use ThreadSignaler explicitly ## What changes were proposed in this pull request? ScalaTest 3.0 uses an implicit `Signaler`. This PR makes it sure all Spark tests uses `ThreadSignaler`