examples: update libvirt path (#442)

In the how-to-create-a-bridge-with-a-vlan-for-libvirtd section, the correct path to where libvirtd creates the config file is /etc/libvirt/qemu/networks/

Apologies if this is not the correct process to report this. I found there was no tag to report documentation errors on Launchpad.

doc/examples.md

@@ -324,7 +324,7 @@ network:
       link: enp0s25
 ```
 
-Then libvirtd would be configured to use this bridge by adding the following content to a new XML file under `/etc/libvirtd/qemu/networks/`. The name of the bridge in the <bridge> tag as well as in <name> need to match the name of the bridge device configured using Netplan:
+Then libvirtd would be configured to use this bridge by adding the following content to a new XML file under `/etc/libvirt/qemu/networks/`. The name of the bridge in the <bridge> tag as well as in <name> need to match the name of the bridge device configured using Netplan:
 
 ```xml
 <network>