Update OSRF package URL to follow server change

.travis.yml

@@ -38,7 +38,7 @@ matrix:
     - env: ROS_DISTRO=kinetic ROSWS=wstool BUILDER=catkin USE_DEB=false
 before_install:
   # Install openrtm_aist & add osrf
-  - export BEFORE_SCRIPT="sudo apt-get install -qq -y ros-${ROS_DISTRO}-openrtm-aist; sudo -E sh -c 'echo \"deb http://packages.osrfoundation.org/drc/ubuntu \`lsb_release -cs\` main\" > /etc/apt/sources.list.d/drc-latest.list'; wget http://packages.osrfoundation.org/drc.key -O - | sudo apt-key add -; sudo apt-get update -qq"
+  - export BEFORE_SCRIPT="sudo apt-get install -qq -y ros-${ROS_DISTRO}-openrtm-aist; sudo -E sh -c 'echo \"deb http://packages.osrfoundation.org/gazebo/ubuntu-stable \`lsb_release -cs\` main\" > /etc/apt/sources.list.d/gazebo-latest.list'; wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -; sudo apt-get update -qq"
   # On kinetic, drcsim is not released
   - if [ ${ROS_DISTRO} != "kinetic" ] ; then export BEFORE_SCRIPT="${BEFORE_SCRIPT}; sudo apt-get install -qq -y drcsim"; fi
   - if [ $USE_DEB == true ] ; then mkdir -p ~/ros/ws_rtmros_gazebo/src; fi