TL;DR Replace your init script with this one. It uses sudo to change to the RabbitMQ user before starting, stopping, and checking the status.

Here's a link that corroborates what I found:

We're doing an upgrade of RabbitMQ here at Weebly. Moving from a CentOS 5 single node to CentOS 6 with DRBD and Pacemaker. Going from RabbitMQ 2.old-and-busted to How hard could it be? Well a few things.