systemd: Replace Requires with BindTo+After for main socket

This is the strongest relationship that can be declared between
two units, and causes the service to be terminated immediately
if its main socket disappears. This is the behavior we want.

Note that we don't do the same for the read-only/admin sockets,
because those are not as critical for the core functionality of
services as the main socket it.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/locking/virtlockd.service.in

@@ -1,7 +1,8 @@
 [Unit]
 Description=Virtual machine lock manager
-Requires=virtlockd.socket
+BindsTo=virtlockd.socket
 Requires=virtlockd-admin.socket
+After=virtlockd.socket
 Before=libvirtd.service
 Documentation=man:virtlockd(8)
 Documentation=https://libvirt.org

src/logging/virtlogd.service.in

@@ -1,7 +1,8 @@
 [Unit]
 Description=Virtual machine log manager
-Requires=virtlogd.socket
+BindsTo=virtlogd.socket
 Requires=virtlogd-admin.socket
+After=virtlogd.socket
 Before=libvirtd.service
 Documentation=man:virtlogd(8)
 Documentation=https://libvirt.org

src/virtd.service.in

@@ -1,8 +1,9 @@
 [Unit]
 Description=@name@ daemon
-Requires=@service@.socket
+BindsTo=@service@.socket
 Requires=@service@-ro.socket
 Requires=@service@-admin.socket
+After=@service@.socket
 Conflicts=libvirtd.service
 After=libvirtd.service
 After=network.target