With the addition of the variable
`om_enable_rabbitmq_high_availability`, this feature in the upgrade
task should be brought back. It is also now used in the deploy task. The
`ha-all` policy is cleared only when
`om_enable_rabbitmq_high_availability` is set to `false`.

Change-Id: Ia056aa40e996b1f0fed43c0f672466c7e4a2f547