Configuring systemd to restart libvirt on failure

This will create a respawn behaviour in case libvirt
process exits due to nonzero exit code, is terminated
by a signal, an operation times out or the configured
watchdog timeout is triggered.
see http://www.freedesktop.org/software/systemd/man/systemd.service.html
and https://bugzilla.redhat.com/show_bug.cgi?id=981974Signed-off-by: NEric Blake <eblake@redhat.com>

daemon/libvirtd.service.in

@@ -15,6 +15,7 @@ EnvironmentFile=-/etc/sysconfig/libvirtd
 ExecStart=@sbindir@/libvirtd $LIBVIRTD_ARGS
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process
+Restart=on-failure
 # Override the maximum number of opened files
 #LimitNOFILE=2048