osstest: remove the loader timeout from the install image

osstest: remove the loader timeout from the install image

When the FreeBSD installer is booted on the godello{0/1} boxes it
receives spurious key strokes. This doesn't happen so far when booted
from disk, or with any other boxes.

In order to cope with this remove the loader timeout on the install
image. Note that failure to boot will still drop the loader into a
manual prompt.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>