Fix installation of documentation for newer rpm
    
    Newer versions of rpm no longer grab everything in the pkgdocdir when
    the %doc macro is used.  That means that the xml examples installed to
    /usr/share/doc/%{name}/config were no longer being installed.  This
    commit changes the spec to eliminate the use of the %doc macro, and
    instead treat the files installed to the doc directory by the package
    the same as all of the other installed files (using the pkgdocdir
    macro).
    
    See also:
    https://fedorahosted.org/fpc/ticket/338
    https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Documentation