Added metadata flag for nested virtualization

As requested in this Trello card, this commit adds a nested virtualization
flag to the compute metadata by checking /proc/cpuinfo for the hypervisor
flag.

https://trello.com/c/24QvbT8m/127-check-site-add-a-check-for-kvm-intel-have-nested-1

Change-Id: I7a7dc30ae9bccf7dca2f296f83661899cbe9a96b

ansible/gather/roles/compute/tasks/main.yml

@@ -24,3 +24,19 @@
   set_fact:
     openstack_neutron_ovsdb: "vsctl"
   when: (ovsdb_status.stdout.find('native') == -1 and ovsdb_status.stdout.find('vsctl') == -1)
+
+
+- name: Check for Nested Virtualization
+  shell: cat /proc/cpuinfo | grep hypervisor
+  register: nested_virt
+  ignore_errors: true
+
+- name: Set Nested Virtualization flag
+  set_fact:
+    openstack_nested_virt: true
+  when: nested_virt.stdout != ""
+
+- name: Set Nested Virtualization flag
+  set_fact:
+    openstack_nested_virt: false
+  when: nested_virt.stdout == ""