the other day one of my friend asked me a question that he accidentally renamed a folder in ubuntu in /var/log and then later couldnt remember what was the original folder name before change. He did it from GUI.
If this is true, then it seems that he had /var/log open in nautilus as root.
In general, its a very bad idea to run a GUI as root.
Chances are that it should fix itself. You could check the contents of the files in
against /var/log/. This should cover the non-empty directories in /var/log. Personally, I wouldn't bother since it is likely that the directories & files will get automatically recreated.