title: OpenCV 3.1.0 finds CUDA 7.5 instead of 8.0
body: <p>I installed OpenCV 3.1.0 and CUDA 8.0 in Ubuntu 16.04. When I check "nvcc --version" to check the CUDA version, it is 8.0. But when I try to compile a C++ OpenCV program I get the following error: </p>
  
  <pre><code>Could NOT find CUDA: Found unsuitable version "7.5", but required 
  is exact version "8.0" (found /usr/local/cuda)
  </code></pre>
  
  <p>So OpenCV tells it founds version 7.5 when the only installed one is 8.0.
  Both CUDA and OpenCV work well toguether in python with no error.</p>
  
  <p>Any idea about what is happening?</p>