message: remove a redundant option.
diff: @@ -1624,7 +1624,7 @@ endif()
  macro(ocv_git_describe var_name path)
  if(GIT_FOUND)
  - execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --tags --exact-match --dirty
  + execute_process(COMMAND "${GIT_EXECUTABLE}" describe --tags --exact-match --dirty
  WORKING_DIRECTORY "${path}"
  OUTPUT_VARIABLE ${var_name}
  RESULT_VARIABLE GIT_RESULT
  