Fixed CMake warnings/bugs caused by #1670 and #1714

include() doesn't create a variable scope, so the settings of
CMAKE_MODULE_PATH and CMAKE_FIND_ROOT_PATH_MODE_* were polluting
everything included after OpenCVDetectCUDA.cmake.

Also, FindCUDA includes FindPackageHandleStandardArgs, which includes
CMakeParseArguments, which causes warnings related to policy CMP0017.
Setting it to NEW seems safe enough.

CMakeLists.txt

@@ -39,6 +39,10 @@ else()
   cmake_minimum_required(VERSION 2.6.3)
 endif()
 
+if(POLICY CMP0017)
+  cmake_policy(SET CMP0017 NEW)
+endif()
+
 if(POLICY CMP0022)
   cmake_policy(SET CMP0022 OLD)
 endif()

cmake/OpenCVDetectCUDA.cmake

@@ -15,12 +15,22 @@ endif()
 
 set(CMAKE_MODULE_PATH "${OpenCV_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
 
+foreach(var INCLUDE LIBRARY PROGRAM)
+  set(__old_frpm_${var} "${CMAKE_FIND_ROOT_PATH_MODE_${var}}")
+endforeach()
+
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
 set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE NEVER)
 
 find_package(CUDA 4.2 QUIET)
 
+foreach(var INCLUDE LIBRARY PROGRAM)
+  set(CMAKE_FIND_ROOT_PATH_MODE_${var} "${__old_frpm_${var}}")
+endforeach()
+
+list(REMOVE_AT CMAKE_MODULE_PATH 0)
+
 if(CUDA_FOUND)
   set(HAVE_CUDA 1)