[SPARK-7991] [PySpark] Adding support for passing lists to describe.
[SPARK-7991] [PySpark] Adding support for passing lists to describe.

This is a minor change.

Author: amey <amey@skytree.net>

Closes #6655 from ameyc/JIRA-7991/support-passing-list-to-describe and squashes the following commits:

e8a1dff [amey] Adding support for passing lists to describe.

(cherry picked from commit 356a4a9b93a1eeedb910c6bccc0abadf59e4877f)
Signed-off-by: Reynold Xin <c9d35a384bc579d1c6c8c055f2a2b5c04e11b521@databricks.com>

andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap