webadmin: Fix vNIC widget behavior

The relatively recent adjustment of the widget to allow
arbitrary-length labels caused labels to always appear as enabled -
this patch properly renders them again.

Change-Id: I76cf6c99f5e894470396751fee533e67f04bbcb3
Bug-Url: https://bugzilla.redhat.com/1086259
Signed-off-by: Lior Vernia <lvernia@redhat.com>