CA-98753: Correct ha_restart_priority for VMs imported on post-6.0.0

When VMs were exported from pre-6.0.0 hosts, they could have ha_restart_priority set to 0,1,2,3 . When these VMs are imported on post-6.0.0 hosts and HA is enabled, they error out. 

This patch aims to correct this field during import hence preventing any error while HA is enabled.