SPARK-6671
Currently using the spark-daemon.sh script we can start and stop the spark demons. But we cannot get the status of the daemons. It will be nice to include the status command in the spark-daemon.sh script, through which we can know if the spark demon is alive or not.

Author: Pradeep Chanumolu <pchanumolu@maprtech.com>

Closes #5327 from pchanumolu/master and squashes the following commits:

d3a1f05 [Pradeep Chanumolu] Make status command check consistent with Stop command
5062926 [Pradeep Chanumolu] Fix indentation in spark-daemon.sh
3e66bc8 [Pradeep Chanumolu] SPARK-6671 : Add status command to spark daemons
1ac3918 [Pradeep Chanumolu] Add status command to spark-daemon