Auto repair libvirt's vnet interfaces

Re-attach network interfaces by getting the info
about them from the current libvirt definitions to
repair guests connectivity with the host.

Change-Id: I2ad7a46c61cd1fd20e89f0688c9427b89a8c2b18
Closes-Bug: PROD-29603
(cherry picked from commit 6e3042b132806373ce83aad36c682c609a5bfd0d)
diff --git a/README.rst b/README.rst
index a8373d3..2bfd2c6 100644
--- a/README.rst
+++ b/README.rst
@@ -1949,6 +1949,14 @@
       network:
         tap_custom_txqueuelen: 10000
 
+Auto repair/re-attach libvirt's vnet interfaces:
+
+.. code-block:: yaml
+
+    linux:
+      network:
+        libvirt_vnet_repair: true
+
 DPDK OVS interfaces
 
 **DPDK OVS NIC**