docs: adapt filling of <head> section for rst2html output
docs: adapt filling of <head> section for rst2html output

The HTML from rst2html doesn't have <h1> immediately under the <body>
tag, instead there is at least one <div> in between.

There are also many things added in the <head> section that we don't
want to have copied over, since our templating system already adds
suitable <head> elements.

We only need to copy the <script> to make index.html work.

Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Signed-off-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

jfehlig/libvirt,zippy2/libvirt,olafhering/libvirt,libvirt/libvirt,zippy2/libvirt,olafhering/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jfehlig/libvirt,nertpinx/libvirt,nertpinx/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,libvirt/libvirt,libvirt/libvirt,jardasgit/libvirt,jardasgit/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jfehlig/libvirt,crobinso/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,crobinso/libvirt,jardasgit/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt