message: Update OpenCVDownload.cmake to fix log crash
  This suppresses the interpretation of string literals by switching the ocv_download_log from a macro to a function.
  This avoid crashes when the string to log contains escape characters.
  More details about the problem this PR fixes are available at:
diff: @@ -34,9 +34,9 @@ file(WRITE "${OPENCV_DOWNLOAD_LOG}" "use_cache \"${OPENCV_DOWNLOAD_PATH}\"\n")
  function(ocv_download)
  cmake_parse_arguments(DL "UNPACK;RELATIVE_URL" "FILENAME;HASH;DESTINATION_DIR;ID;STATUS" "URL" ${ARGN})
  - macro(ocv_download_log)
  + function(ocv_download_log)
  file(APPEND "${OPENCV_DOWNLOAD_LOG}" "${ARGN}\n")
  - endmacro()
  + endfunction()
  ocv_assert(DL_FILENAME)
  ocv_assert(DL_HASH)
  