webadmin: tiny fix for make template dialog's focus traversal

The tab index of 'Quota' combobox is wrong, resulting in wrong focus
traversal order.

This patch fix it by giving the 'Quota' combobox the right tab index so
that it will be focused right after 'Host Cluster' combobox.

Change-Id: If10096e8f9e1141d2d0a46a600b0e82e849b59ba
Bug-Url: https://bugzilla.redhat.com/873133
Signed-off-by: Arik Hadas <ahadas@redhat.com>