Fixed the installation of library directories

Author: Ton Kersten <github@tonkersten.com>
Date:   Mon Apr 29 10:44:30 2013 +0200

    Fixed the installation of library directories

    When running install the `setup.py` give error

    changing mode of /usr/bin/ansible-doc to 755
    running install_data
    error: can't copy './library/utilities': doesn't exist or not a regular file
    make: *** [install] Error 1

    While debugging and chatting on IRC 'benno' came up with this patch, which works on
    CentOS 6.4 and on Ubuntu.