Fix OpenCV --with-cuda compilation on 10.9 and CUDA 6.0

Without the patch, I get the following error:
```
ld: can't map file, errno=22 file '/usr/local/cuda' for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [lib/libopencv_core.2.4.9.dylib] Error 1
make[1]: *** [modules/core/CMakeFiles/opencv_core.dir/all] Error 2
make: *** [all] Error 2
```
for
```
==> Configuration
HOMEBREW_VERSION: 0.9.5
HEAD: 84320769f3cfe3f147241fd239697932124939ae
CPU: 8-core 64-bit haswell
OS X: 10.9.3-x86_64
Xcode: 5.1.1
CLT: 5.1.0.0.1.1396320587
X11: 2.7.5 => /opt/X11
==> ENV
HOMEBREW_CC: clang
HOMEBREW_CXX: clang++
MAKEFLAGS: -j8
CMAKE_PREFIX_PATH: /usr/local
CMAKE_INCLUDE_PATH: /usr/include/libxml2:/System/Library/Frameworks/OpenGL.framework/Versions/Current/Headers
CMAKE_LIBRARY_PATH: /System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries
CMAKE_FRAMEWORK_PATH: /usr/local/opt/python/Frameworks
PKG_CONFIG_PATH: /usr/local/opt/libpng/lib/pkgconfig:/usr/local/opt/libtiff/lib/pkgconfig
PKG_CONFIG_LIBDIR: /usr/lib/pkgconfig:/usr/local/Library/ENV/pkgconfig/10.9
ACLOCAL_PATH: /usr/local/share/aclocal
PATH: /usr/local/opt/python/bin:/usr/local/Library/ENV/4.3:/usr/local/opt/cmake/bin:/usr/local/opt/jpeg/bin:/usr/local/opt/libpng/bin:/usr/local/opt/libtiff/bin:/usr/local/opt/pkg-config/bin:/usr/local/opt/python/bin:/usr/bin:/bin:/usr/sbin:/sbin

Error: opencv 2.4.9 did not build
```