cpu_conf: Fix XPath for parsing TSC frequency
cpu_conf: Fix XPath for parsing TSC frequency

Due to this bug the following command would fail on any host where TSC
frequency can be probed:

    $ virsh capabilities | virsh cpu-baseline /dev/stdin
    error: unsupported configuration: Invalid TSC frequency

https://bugzilla.redhat.com/show_bug.cgi?id=1641702

Signed-off-by: Jiri Denemark <62bdf77dc47919a4d59a91822129d14633cfca81@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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