Add ros interface environment variable

[sktometometo]

Add NETWORK_DEFAULT_ROS_INTERFACE to config.bash and use it in supervisor conf as

rossetclient $NETWORK_DEFAULT_ROS_INTERFACE

to set ROS_IP or ROS_HOSTNAME.

By default, NETWORK_DEFAULT_ROS_INTERFACE is set to hostname of the robots.
When executing rossetclient fetch1075, ROS_IP is not set and ROS_HOSTNAME is set to fetch1075.

Please see config.bash for more detailed examples and see jsk-ros-pkg/jsk_common#1746 for details about rossetclient.