msi: add support for MSIRUNMODE_REBOOTNOW in MsiGetMode

[Hans Leidekker]

On Fri, 2012-03-30 at 17:27 -0700, Austin English wrote:
> +    case MSIRUNMODE_REBOOTNOW:
> +        r = package->need_reboot;
> +        break;
> + 

MSIRUNMODE_REBOOTNOW and MSIRUNMODE_REBOOTATEND are not the same thing.