Tutorial "Writing a Simple Service and Client", i modified the wrong file, what can i do?

Hey, I wish to learn ros and I started by doing the tutorials available on ros.org. But in the "Writing a Simple Service and Client" tutorial, when it say to modify the file `~/catkin_ws/src/beginner_tutorials/CMakeLists.txt`. I modified the secure file that is in `~/catkin_ws/src` using `sudo gedit CMakeLists`. Before that, it worked but now I have a mistake when I do `catkin_make`. CMake Error at /opt/ros/kinetic/share/genmsg/cmake/genmsg-extras.cmake:94 (message): add_message_files() directory not found: /home/audensiel/catkin_ws/src/msg Call Stack (most recent call first): CMakeLists.txt:9 (add_message_files) -- Configuring incomplete, errors occurred! See also "/home/audensiel/catkin_ws/build/CMakeFiles/CMakeOutput.log". See also "/home/audensiel/catkin_ws/build/CMakeFiles/CMakeError.log". Invoking "cmake" failed When I remove all files and folders and I restart at the beginning (the tutorials), and i created `mkdir -p ~/catkin_ws/src` ... The file I modified previously is always the same. I think this is my problem, so if someone can give me the contents of this file or tell me how to retrieve the original. Thank for your help. William