Install systemd-coredump on Debian-based distros

On Debian-based distros, the 'coredumpctl' command is
provided by the systemd-coredump package, which is not
installed by default. On failure, when "post" commands
are executed this error is seen:

  controller | /bin/bash: line 1: coredumpctl: command not found

Install it along with other libvirt packages to avoid
the error.

On Fedora distros it is in the systemd package, so the
problem is not seen since it is always installed.

Change-Id: I6012bd3240d68736a5db8ae49dc32098a086f320
diff --git a/lib/nova_plugins/functions-libvirt b/lib/nova_plugins/functions-libvirt
index 7992306..ba2e98e 100644
--- a/lib/nova_plugins/functions-libvirt
+++ b/lib/nova_plugins/functions-libvirt
@@ -69,7 +69,7 @@
             $REQUIREMENTS_DIR/upper-constraints.txt -- libvirt-python
 
     if is_ubuntu; then
-        install_package qemu-system libvirt-clients libvirt-daemon-system libvirt-dev python3-libvirt
+        install_package qemu-system libvirt-clients libvirt-daemon-system libvirt-dev python3-libvirt systemd-coredump
         if is_arch "aarch64"; then
             install_package qemu-efi
         fi