Fix gnt-cluster modify -H and offline nodes
Fix gnt-cluster modify -H and offline nodes

Reviewed-by: ultrotter

grnet/snf-ganeti,dimara/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti,andir/ganeti,ganeti/ganeti,andir/ganeti,dimara/ganeti,yiannist/ganeti,apyrgio/snf-ganeti,leshchevds/ganeti,mbakke/ganeti,mbakke/ganeti,ganeti/ganeti,leshchevds/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,bitemyapp/ganeti,ganeti/ganeti,andir/ganeti,bitemyapp/ganeti,apyrgio/ganeti,ganeti-github-testing/ganeti-test-1,apyrgio/ganeti,onponomarev/ganeti,grnet/snf-ganeti,yiannist/ganeti,leshchevds/ganeti