Update samples/cpp/example_cmake: no need to use `include_directories`

samples/cpp/example_cmake/CMakeLists.txt

@@ -18,8 +18,10 @@ message(STATUS "    version: ${OpenCV_VERSION}")
 message(STATUS "    libraries: ${OpenCV_LIBS}")
 message(STATUS "    include path: ${OpenCV_INCLUDE_DIRS}")
 
-# Add OpenCV headers location to your include paths
-include_directories(${OpenCV_INCLUDE_DIRS})
+if(CMAKE_VERSION VERSION_LESS "2.8.11")
+  # Add OpenCV headers location to your include paths
+  include_directories(${OpenCV_INCLUDE_DIRS})
+endif()
 
 # Declare the executable target built from your sources
 add_executable(opencv_example example.cpp)