webadmin: fix QoS dialog indentation

Labels will be positions above the fields, instead
of next to it (to avoid other locale issues).

Also fixed unnecessary dialog scroll bars, and adjusted
dialog width.

Change-Id: Ifbcfa6849284d2e087c6884aa79cd77d9f4c3096
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>