Deletes the specified policy.A policy cannot be deleted if it has non-default versions or it is attached to any certificate.To delete a policy, use the DeletePolicyVersion action to delete all non-default versions of the policy; use the DetachPolicy action to detach the policy from any certificate; and then use the DeletePolicy action to delete the policy.When a policy is deleted using DeletePolicy, its default version is deleted with it.Requires permission to access the DeletePolicy action.