engine, webadmin: Inconsistent maintenance mode handling via host-deploy

When the host is reinstalled a new check box is
presented that lets the host be activated after
reinstall.

Change-Id: Ic90eb22664ead14fbe64523fbd4f42cd02ab1601
Bug-Url: https://bugzilla.redhat.com/1087524
Signed-off-by: Ravi Nori <rnori@redhat.com>