To suppress the error, header should use the pcl_conversions in hydro ac...

...cording to http://wiki.ros.org/hydro/Migration#PCL

I got the error below. This PR will suppress the error.

/home/*****/catkin_ws/src/softkinetic/softkinetic_camera/src/softkinetic_start.cpp: function ‘void onNewDepthSample(DepthSense::DepthNode, DepthSense::DepthNode::NewSampleReceivedData)’ :
/home/*****/catkin_ws/src/softkinetic/softkinetic_camera/src/softkinetic_start.cpp:173:41: error: cannot convert ‘ros::Time’ to ‘uint64_t {aka long unsigned int}’ in assignment