webadmin: show subtab after reveal

- Fixed showing the subtab before the reveal happened. This
caused previous subtabs to flicker an old subtab when on a
different subtab.

Change-Id: Ifafcc372e9b8e71c89bd1b7ed80cf4c40f828569
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=916207
Signed-off-by: Alexander Wels <awels@redhat.com>