webadmin: disable hot plug for disk with IDE interface

New disk dialog:
when the VM is running and IDE is selected,
'Activate' should be disabled.

Change-Id: Iff166bfdae2e7bcdd56c5e4e5311f878138c260a
Bug-Url: https://bugzilla.redhat.com/1055403
Signed-off-by: Daniel Erez <derez@redhat.com>