remove workarounds for avoiding HA fencing on upgrade

those got introduced by commit
ec826d72c06e6f649b2b19c3341c39abb29b19f9 and can now be safely
removed, as current pve-cluster and pve-ha-manager do show this
problems, and upgrades need to go through latest PVE 5.X which then
ensures this is fixed.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>