Author: Ted Blackman <ted.blackman@gmail.com>

Closes #6656 from belisarius222/branch-1.4 and squashes the following commits:

747cbc2 [Ted Blackman] [SPARK-8116][PYSPARK] Allow sc.range() to take a single argument.

(cherry picked from commit f02af7c8)
Signed-off-by: Reynold Xin <rxin@databricks.com>