Update setupMongoNode.sh

Theres a minor problem with some Mongo System V init scripts (Centos, mongodb-org-2.6.5-1.x86_64) that blocks this setupMongoNode.sh from running fully and smoothly.

When using service in the script it throws a "dirname: missing operand" which prevents the Mongo Javascript initialization from running.

And the culprit is in /etc/init.d/mongod

PIDDIR=`dirname $PIDFILE`

One can view the error each time with 

sudo service mongod start
dirname: missing operand
Try `dirname --help' for more information.