[SPARK-8395] [DOCS] start-slave.sh docs incorrect
[SPARK-8395] [DOCS] start-slave.sh docs incorrect

start-slave.sh no longer takes a worker # param in 1.4+

Author: Sean Owen <sowen@cloudera.com>

Closes #6855 from srowen/SPARK-8395 and squashes the following commits:

300278e [Sean Owen] start-slave.sh no longer takes a worker # param in 1.4+

(cherry picked from commit f005be02730db315e2a6d4dbecedfd2562b9ef1f)
Signed-off-by: Andrew Or <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@databricks.com>

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