create RobotHardware_gazebo.so for hrpsys_gazebo_general

based on https://github.com/start-jsk/rtmros_gazebo/issues/35, carete RobotHardware_gazebo for gazebo/hrpsys setup
this patch requires https://github.com/start-jsk/hrpsys/pull/87
@mmurooka please confirm this patch ans also update launch files