disabled gcc 4.8 warning

It looks like a GCC 4.8 bug:

```
In file included from .../opencv/modules/core/include/opencv2/core/cuda.hpp:692:0,
                 from .../build/modules/superres/precomp.hpp:51:
.../opencv/modules/core/include/opencv2/core/cuda.inl.hpp: In member function 'virtual cv::AlgorithmInfo* {anonymous}::PyrLK_CUDA::info() const':
.../opencv/modules/core/include/opencv2/core/cuda.inl.hpp:114:14: warning: array subscript is above array bounds [-Warray-bounds]
     release();
              ^
```
gcc version 4.8.2 20131017 (Red Hat 4.8.2-1) (GCC)