Update Cirros image to 0.6.2

LIBVIRT_CPU_MODE: host-passthrough was commented
as there was some issue with 0.6.1. 0.6.2 is known
to have the fix included, so let's use that instead.

Change-Id: I534d537400fa67796a64a550b3fe45a3b28f250e
diff --git a/zuul.d/base-nested-switch.yaml b/zuul.d/base-nested-switch.yaml
index 760e5a1..f407d8f 100644
--- a/zuul.d/base-nested-switch.yaml
+++ b/zuul.d/base-nested-switch.yaml
@@ -29,11 +29,10 @@
     vars: &nested_virt_vars
       devstack_localrc:
         LIBVIRT_TYPE: kvm
-        # cirros 0.6.1 not booting when host-passthrough is used
-        # LIBVIRT_CPU_MODE: host-passthrough
-        CIRROS_VERSION: 0.6.1
-        DEFAULT_IMAGE_NAME: cirros-0.6.1-x86_64-disk
-        DEFAULT_IMAGE_FILE_NAME: cirros-0.6.1-x86_64-disk.img
+        LIBVIRT_CPU_MODE: host-passthrough
+        CIRROS_VERSION: 0.6.2
+        DEFAULT_IMAGE_NAME: cirros-0.6.2-x86_64-disk
+        DEFAULT_IMAGE_FILE_NAME: cirros-0.6.2-x86_64-disk.img
 
 # Base nested switch job for yoga and zed
 - job: