webadmin: Filter domains on disk move dialog from main disk tab

Since we currently do not support live storage migration from block domains
to file domains and vice versa, the destination domains list will be filtered
when moving a disk that is plugged to a running VM (from the main disks tab)

Change-Id: Ia28d3acd7ceeaff07745f16af920f8d225e485c7
Signed-off-by: Tal Nisan <tnisan@redhat.com>
Bug-Url: https://bugzilla.redhat.com/1073343