use boost::placeholders::_1/_2 instead of deprecated _1/_2

[lucasw]

When building on newer systems this error results, using boost::placeholders fixes it:

/home/lucasw/base_catkin_ws/src/ros/libuvc_ros/libuvc_camera/src/camera_driver.cpp: In member function ‘bool libuvc_camera::CameraDriver::Start()’:
/home/lucasw/base_catkin_ws/src/ros/libuvc_ros/libuvc_camera/src/camera_driver.cpp:81:84: error: ‘_1’ was not declared in this scope
   81 |   config_server_.setCallback(boost::bind(&CameraDriver::ReconfigureCallback, this, _1, _2));