Investigate and possibly remove hostname option in docker-compose

[nicholasadr]

Adding hostname customization in docker-compose will break the container network if the following option is used in docker-compose in ROS application:

network_mode: "host"

The error is as follows:

RLException Unable to contact my own server at [http://docker:40287/].
This usually means that the network is not configured properly.

A common cause is that the machine cannot ping itself. Please check
for errors by running:

ping docker

For more tips, please see

http://www.ros.org/wiki/ROS/NetworkSetup