wildcard %doc flagging - anything under _pkgdocdir
    
    This changes only purely metadata-related information, specifically
    what rpm --docfiles prints. The actual documentation files are already
    included in the RPM by %dir.
    
    Testing on RHEL6 with both rpm -ql and rpm -qd, no change could be
    observed in the final generated RPM, so this change should have no
    impact on anything working with the final RPM itself.
    
    Signed-off-by: Jiri Jaburek <jjaburek@redhat.com>