Avoid Bashrc exports

[yycho0108]

We can probably make everyone's lives easier by simply adding to the export tag in pr2_robot/package.xml:

<run_depend>gazebo_ros</run_depend>
<export>
<gazebo_ros gazebo_model_path="${prefix}/models"/>
</export>

This way all you need to do is catkin_make or catkin build and no one needs to remember to modify the .bashrc file.

As we all know, this export path can be verified as follows:

rospack plugins --attrib gazebo_model_path gazebo_ros