Previous commit moved some lists out of the -devel package
and into the -docs package

  commit feffcc03
  Author: Cole Robinson <crobinso@redhat.com>
  Date:   Wed Apr 13 10:37:42 2016 -0400

    spec: Only pull in API docs with -devel package

What was not realized is that the rule 'libvirt-docs/*'
and ' docs/*.html docs/html docs/*.gif' actually point
to the exact same content. ie, we had previously included
the website HTML in *both* the -docs and -devel packages.

So this change ended up listing the files twice, which
caused RPM to print a load of warnings:

warning: File listed twice: /usr/share/doc/libvirt-docs/html
warning: File listed twice: /usr/share/doc/libvirt-docs/html/32favicon.png
warning: File listed twice: /usr/share/doc/libvirt-docs/html/404.html
warning: File listed twice: /usr/share/doc/libvirt-docs/html/acl.html
warning: File listed twice: /usr/share/doc/libvirt-docs/html/aclpolkit.html
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>