KVM netscript: add static routes, with no suffix

The /32 suffix is useless, since the kernel already assumes single-host,
if no suffix is specified. Moreover we prefer these routes to be
"static" so that routing daemons, if present, won't mess with them.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>