gazebo2rviz: correct branch aka use "version" aka git branch field correctly; also add to indigo

Refering to https://github.com/ros/rosdistro/commit/882d80a5eaf5eec1541079b726b330b5c801494f#commitcomment-6529897

BTW: http://docs.ros.org/api/rospkg/html/distro_format.html is not available, is there more up to date information about what each field means?