multi-machine setup is not working on Moe

[Kukanani]

Specifically on Moe,

This is likely related to the fact that we wiped and rebuild moe1. Possible solutions:

• Carefully re-define the ROS environment variables (ROS_IP and ROS_MASTER_URI) on moe1 and moe2
• Fix the etc/hosts files on moe1 and moe2
• Some router configuration issue? Although the machines can ping each other just fine.

[Kukanani]

Fixed in robot_setup @75e3d6a.

There were several interacting issues, including:

• Using the wireless rather than local IP address when setting ROS_IP
• Setting ROS_HOSTNAME, which is redundant
• Setting ROS_MASTER_URI incorrectly on moe1