rewrite add_test command for accuracy tests:

* use new syntax introduced in CMake 2.8.0
* set OPENCV_TEST_DATA_PATH enviroment property

cmake/OpenCVModule.cmake

@@ -812,11 +812,15 @@ function(ocv_add_accuracy_tests)
         set_target_properties(${the_target} PROPERTIES FOLDER "tests accuracy")
       endif()
 
-      enable_testing()
-      get_target_property(LOC ${the_target} LOCATION)
-      add_test(${the_target} "${LOC}")
-
       ocv_add_precompiled_headers(${the_target})
+
+      if(CMAKE_VERSION VERSION_GREATER "2.8" AND OPENCV_TEST_DATA_PATH)
+        add_test(NAME ${the_target} COMMAND ${the_target})
+
+        set_tests_properties(${the_target} PROPERTIES
+          ENVIRONMENT "OPENCV_TEST_DATA_PATH=${OPENCV_TEST_DATA_PATH}")
+      endif()
+
     else(OCV_DEPENDENCIES_FOUND)
       # TODO: warn about unsatisfied dependencies
     endif(OCV_DEPENDENCIES_FOUND)