Fix gazebo6 deprecation warnings

Several RaySensor functions are deprecated in gazebo6
and are removed in gazebo7.
The return type is changed to use ignition math
and the function name is changed.
This adds ifdef's to handle the changes.

gazebo_plugins/src/gazebo_ros_block_laser.cpp

@@ -230,8 +230,13 @@ void GazeboRosBlockLaser::PutLaserData(common::Time &_updateTime)
 
   this->parent_ray_sensor_->SetActive(false);
 
+#if GAZEBO_MAJOR_VERSION >= 6
+  auto maxAngle = this->parent_ray_sensor_->AngleMax();
+  auto minAngle = this->parent_ray_sensor_->AngleMin();
+#else
   math::Angle maxAngle = this->parent_ray_sensor_->GetAngleMax();
   math::Angle minAngle = this->parent_ray_sensor_->GetAngleMin();
+#endif
 
   double maxRange = this->parent_ray_sensor_->GetRangeMax();
   double minRange = this->parent_ray_sensor_->GetRangeMin();
@@ -240,8 +245,13 @@ void GazeboRosBlockLaser::PutLaserData(common::Time &_updateTime)
 
   int verticalRayCount = this->parent_ray_sensor_->GetVerticalRayCount();
   int verticalRangeCount = this->parent_ray_sensor_->GetVerticalRangeCount();
+#if GAZEBO_MAJOR_VERSION >= 6
+  auto verticalMaxAngle = this->parent_ray_sensor_->VerticalAngleMax();
+  auto verticalMinAngle = this->parent_ray_sensor_->VerticalAngleMin();
+#else
   math::Angle verticalMaxAngle = this->parent_ray_sensor_->GetVerticalAngleMax();
   math::Angle verticalMinAngle = this->parent_ray_sensor_->GetVerticalAngleMin();
+#endif
 
   double yDiff = maxAngle.Radian() - minAngle.Radian();
   double pDiff = verticalMaxAngle.Radian() - verticalMinAngle.Radian();