webadmin: Fixed table layout upon enableColumnResizing()

This makes sure that column resizing behaves consistently for the
tables in which it's enabled (without it some default browser
rearranging occurs).

Change-Id: Ia36d2d4f1cae395fe9f12d55a05799445d0eca11
Bug-Url: https://bugzilla.redhat.com/1009745
Signed-off-by: Lior Vernia <lvernia@redhat.com>