core: prevent HA VM from being non-migratable

user could define a VM as being HA and also not automatically-migratable.

Changed the canDoAction for AddVM and UpdateVM to prevent this situation

Change-Id: I2a7896ddd829fdd89396057114886acae3d65d10
Signed-off-by: Ofri Masad <omasad@redhat.com>