fix SystemVMs running in Xen HVM mode are not configured (#2760)

- Set hypervisor to xen-hvm when virt-what detects both HyperV cpuid and xen-domU

Author: dpassante

systemvm/debian/opt/cloud/bin/setup/cloud-early-config

@@ -35,8 +35,15 @@ log_it() {
 }
 
 hypervisor() {
-  local try=$([ -x /usr/sbin/virt-what ] && virt-what | tail -1)
-  [ "$try" != "" ] && echo $try && return 0
+  [ -x /usr/sbin/virt-what ] && local facts=( $(virt-what) )
+  if [ "$facts" != "" ]; then
+    # Xen HVM is recognized as Hyperv when Viridian extensions are enabled
+    if [ "${facts[-1]}" == "xen-domU" ] && [ "${facts[0]}" == "hyperv" ]; then
+      echo "xen-hvm" && return 0
+    else
+      echo ${facts[-1]} && return 0
+    fi
+  fi
 
   grep -q QEMU /proc/cpuinfo  && echo "kvm" && return 0
   grep -q QEMU /var/log/messages && echo "kvm" && return 0