webadmin: Reason does not get updated when trying to shutdown a VM which is Powering up of Shutting Down

When trying to stop the VM while it is powering
up or shutting down, the reason comment does not
get saved in the DB

On the second shut down, the reason text box should
be initialized with the former reason text, and the
user will be allowed to edit it as he will

The reason column is populated with the reason only
when a single vm is being shutdown

Change-Id: I0b10ed39563385cf99a366a32eebcc0c5ce08e72
Bug-Url: https://bugzilla.redhat.com/1114903
Signed-off-by: Ravi Nori <rnori@redhat.com>