Fixes #3120: Add an empty robots.txt file to prevent apache logs from beeing cluttered by useless errors
Merge pull request #434 from Kegeruneku/bug_3120/int/3120_add_a_robots_txt_file_to_the_webapp

Fixes #3120: Add an empty robots.txt file to prevent apache logs from be...
Merge branch 'branches/rudder/2.8' of github.com:Normation/rudder into branches/rudder/2.9
Merge branch 'branches/rudder/2.9'