[sahara] Deployment cluster failed w/o internet access

Steps to reproduce:

1. Create a cluster (neutron/vlan, cinder/lvm for volumes enabled)
2. Add 3 controllers (1 CPU, 4Gb of RAM)
3. Add 1 compute ( 4 CPU, 16Gb of RAM )
4. Add 1 cinder ( 1 CPU, 4Gb of RAM, 300Gb disk space)
5. Deploy changes
6. Run OSTF

"Sahara test for launching a simple Vanilla2 cluster" failed: "Cluster failed to build and is in "Error" status."

Sahara image was taken from here: http://sahara-files.mirantis.com/mos70/sahara-kilo-vanilla-2.6.0-ubuntu-14.04.qcow2

In the diagnostic snapshot (see the attach):

### ./node-5.test.domain.local/**NO MATCH**.log

2015-09-15T22:07:30.331865+00:00 err: 22:07:30.328 10561 ERROR sahara.service.ops [-] Error during operating on cluster sahara-cluster-1856647386 (reason: An error occurred in thread 'configure-ntp-sahara-cluster-1856647386-worker-001': RemoteCommandException: Error during command execution: "ntpdate -u pool.ntp.org"
Return code: 1
STDERR:
Error resolving pool.ntp.org: Name or service not known (-2)
15 Sep 22:07:28 ntpdate[1829]: Can't find host pool.ntp.org: Name or service not known (-2)
15 Sep 22:07:28 ntpdate[1829]: no servers can be used, exiting

Error ID: dc625c30-25e3-407a-bb78-ccf5393b4295
Error ID: 0edec0b1-7eca-48f1-9000-95bda8506f90)

2015-09-15T22:07:31.016863+00:00 info: 22:07:31.014 10561 INFO sahara.utils.general [-] Cluster status has been changed: id=51ee7873-7c20-40cf-be64-5c9c1d81eb78, New status=Error