webadmin: disks tab - add listeners on presenter

Adding disk type (All/Image/LUN) change event lister
on 'MainTabDiskPresenter -> onReveal' in order
to ensure listener subscription (currently, since the
listeners are added in the view, it might get
cleared upon staling the list model).

Change-Id: I0a0e76d5c21c1420232b12a6cbf2d65ff2851c09
Bug-Url: https://bugzilla.redhat.com/1019659
Signed-off-by: Daniel Erez <derez@redhat.com>
webadmin: clear connection on import SD rollback

In order to avoid stale connections data in the DB,
clear storage connection when an export/iso domain
doesn't exist on the specified path
(GetExistingStorageDomainList returns an empty list)

Change-Id: Ia2e70353494ce97a6c2ae0ad74868c1f502a309c
Bug-Url: https://bugzilla.redhat.com/1020812
Signed-off-by: Daniel Erez <derez@redhat.com>
webadmin: clean connection on new GlusterFS failure

StorageListModel -> saveNewGlusterStorage() ->
AddStorageServerConnection:
Set connection ID (using action's return value) to enable connection
clean-up on failure [as 'StorageListModel -> cleanConnection()' invokes
RemoveStorageServerConnection iff connection's ID exists].

Change-Id: Id50f5230e5548e50ff17a7bc6af1bf098ccb8c15
Bug-Url: https://bugzilla.redhat.com/1021882
Signed-off-by: Daniel Erez <derez@redhat.com>