systemd: do not use default dependencies for clvmd/cmirrord units

Do not use default dependencies that systemd adds to the units
so we have better control of when the service is started/stopped
and we don't end up with unexpected behaviour.

scripts/lvm2_cluster_activation_systemd_red_hat.service.in

@@ -3,7 +3,8 @@ Description=Clustered LVM volumes activation service
 Requires=lvm2-clvmd.service
 After=lvm2-clvmd.service lvm2-cmirrord.service
 OnFailure=lvm2-clvmd.service
-DefaultDependencies=false
+DefaultDependencies=no
+Conflicts=shutdown.target
 
 [Service]
 Type=simple

scripts/lvm2_clvmd_systemd_red_hat.service.in

@@ -7,6 +7,8 @@ Requires=network.target dlm.service corosync.service
 RefuseManualStart=true
 RefuseManualStop=true
 StopWhenUnneeded=true
+DefaultDependencies=no
+Conflicts=shutdown.target
 
 [Service]
 Type=forking

scripts/lvm2_cmirrord_systemd_red_hat.service.in

@@ -4,6 +4,8 @@ Documentation=man:cmirrord(8)
 Requires=corosync.service
 After=corosync.service
 Before=remote-fs.target
+DefaultDependencies=no
+Conflicts=shutdown.target
 
 [Service]
 Type=forking