webadmin: align configure firewall checkbox

Reduced width of "configure firewall" checkbox in new host
dialog , so it will be in the same line with its label.
(Before the fix the checkbox was in new line separate from its label)

Change-Id: Id9886c1e6c28bfab5f952455c06f44a7daf7f4c2
Signed-off-by: Alissa Bonas <abonas@redhat.com>