Modify the default Qemu packages name for AArch64.

In Debian jessie and later release,there is no packages
called "qemu-kvm" for AArch64. Also modify the libguestfs0
packages for AArch64

Closes-bug: #1612182

Change-Id: I5eb6bd137896eb9abfc4f8dbb41b41105e4820cd
Signed-off-by: Kevin Zhao <kevin.zhao@linaro.org>
diff --git a/lib/nova_plugins/functions-libvirt b/lib/nova_plugins/functions-libvirt
index 4e5a748..790227b 100644
--- a/lib/nova_plugins/functions-libvirt
+++ b/lib/nova_plugins/functions-libvirt
@@ -23,12 +23,7 @@
 # Installs required distro-specific libvirt packages.
 function install_libvirt {
     if is_ubuntu; then
-        if is_arch "aarch64" && [[ ${DISTRO} == "trusty" ]]; then
-            install_package qemu-system
-        else
-            install_package qemu-kvm
-            install_package libguestfs0
-        fi
+        install_package qemu-system
         install_package libvirt-bin libvirt-dev
         pip_install_gr libvirt-python
         if [[ "$EBTABLES_RACE_FIX" == "True" ]]; then