[libvirt] website: API reference for virterror contains libvirt API also

[Matthias Bolte]

The API reference website [1] for virterror contains the API reference
for virterror as expected. But the complete libvirt API reference,
that is already found at [2], is appended too.

I looked into the XSLT process that generates those two HTML files
from the libvirt-api.xml to understand why this happens, but I
couldn't locate the problem.

[1] http://www.libvirt.org/html/libvirt-virterror.html
[2] http://www.libvirt.org/html/libvirt-libvirt.html

Matthias