virtlogd.socket: Tie lifecycle to libvirtd.service

We already guarantee that virtlogd.socket is enabled/disabled
along with libvirtd.service, but if libvirtd.service has just
been installed and is started before rebooting, then
virtlogd.socket will not be running and guest startup will
fail.

Add Requires=virtlogd.socket to libvirtd.service to make sure
virtlogd.socket is always started along with libvirtd.service,
and add Before=libvirtd.service to both virtlogd.socket and
virtlogd.service so that virtlogd never disappears before
libvirtd has exited.

Also add PartOf=libvirtd.service to both virtlogd.socket and
virtlogd.service, so that virtlogd can be shut down when not
needed.

Resolves: https://bugzilla.redhat.com/1372576
(cherry picked from commit 839a0608)

daemon/libvirtd.service.in

@@ -5,6 +5,7 @@
 
 [Unit]
 Description=Virtualization daemon
+Requires=virtlogd.socket
 Before=libvirt-guests.service
 After=network.target
 After=dbus.service

src/logging/virtlogd.service.in

 [Unit]
 Description=Virtual machine log manager
 Requires=virtlogd.socket
+Before=libvirtd.service
+PartOf=libvirtd.service
 Documentation=man:virtlogd(8)
 Documentation=http://libvirt.org
 

src/logging/virtlogd.socket.in

 [Unit]
 Description=Virtual machine log manager socket
+Before=libvirtd.service
+PartOf=libvirtd.service
 
 [Socket]
 ListenStream=@localstatedir@/run/libvirt/virtlogd-sock