Addition of a rule for stack geographic_info

I'm trying to resolve this question: http://answers.ros.org/question/52547/cannot-locate-rosdep-definition-for-geographicinfo/ . I don't know if the changes that I made will work, because of a bug in rosdep: http://answers.ros.org/question/50660/custom-rosdep-rules/ . I have never used rosdep either. Basically, I'm trying to get rosdep to download the stack geographicinfo when a ROS package depends on it.

P.S. I've never used git before and I don't understand clearly the concepts (forks, push, pull, etc.), so hopefully what I'm doing makes sense.