replace awaitTransformation with awaitTermination in scaladoc/javadoc

Author: Holden Karau <holden@pigscanfly.ca>

Closes #2861 from holdenk/SPARK-4015-Documentation-in-the-streaming-context-references-non-existent-function and squashes the following commits:

081db8a [Holden Karau] fix pyspark streaming doc too
0e03863 [Holden Karau] replace awaitTransformation with awaitTermination