title: Linking Opencv in a project using cmake
body: <p>I have two opencv installed, one is in /usr/local and another one in /usr.
  So /usr/share/OpenCV has OpencvConfig.cmake for Opencv2.4.10 and /usr/local/share/OpenCV has OpencvConfig.cmake for Opencv3.1.0.
  In my project's cmake I set the path for OPencv2.4.10 as</p>
  
  <pre><code>cmake_minimum_required(VERSION 2.8)
  project(five-point-nister)
  
  SET("OpenCV_DIR" "/usr/share/OpenCV")
  find_package( OpenCV REQUIRED )
  
  add_executable(five-point-nister
      five-point.cpp precomp.cpp modelest.cpp)
  target_link_libraries(five-point-nister ${OpenCV_LIBS})
  </code></pre>
  
  <p>But when I compile the project, the project is trying to link to OPencv3.1.0 and the errors are</p>
  
  <pre><code>In file included from /usr/local/include/opencv2/core.hpp:59:0,
                   from /usr/local/include/opencv2/calib3d.hpp:47,
                   from /usr/local/include/opencv2/calib3d/calib3d.hpp:48,
  </code></pre>
  
  <p>By right, it should be <code>/usr/include/opencv2</code>, but now  is <code>/usr/local/include/opencv2</code>. So my project is still linking to Opencv3.1.0.
  How can I correct it?
  Thanks</p>