Refuse to have negative console ttls
Refuse to have negative console ttls

I don't think zero makes a lot of sense either, but at least this is
_some_ sanity checking.

Change-Id: I3d1320d83c056ca2c0ac120b3ed9c46cf5a08f58

rajalokan/nova,sebrandon1/nova,mahak/nova,mikalstill/nova,rahulunair/nova,gooddata/openstack-nova,jianghuaw/nova,gooddata/openstack-nova,cloudbase/nova,hanlind/nova,gooddata/openstack-nova,gooddata/openstack-nova,sebrandon1/nova,vmturbo/nova,rajalokan/nova,openstack/nova,sebrandon1/nova,phenoxim/nova,Juniper/nova,rajalokan/nova,klmitch/nova,klmitch/nova,Juniper/nova,alaski/nova,vmturbo/nova,mikalstill/nova,vmturbo/nova,jianghuaw/nova,klmitch/nova,alaski/nova,openstack/nova,rahulunair/nova,klmitch/nova,mahak/nova,jianghuaw/nova,Juniper/nova,hanlind/nova,openstack/nova,vmturbo/nova,jianghuaw/nova,hanlind/nova,Juniper/nova,phenoxim/nova,mikalstill/nova,rahulunair/nova,cloudbase/nova,cloudbase/nova,rajalokan/nova,mahak/nova