Specify DNS as a list in dhclient config

Ubuntu 14.04 can only process a single prepend for domain-name-servers

Signed-off-by: Maria Shaldibina <mariash@pivotallabs.com>
Restart network for Ubuntu 14.04

/etc/init.d/networking does not restart network in Ubuntu 14.04

Signed-off-by: Maria Shaldibina <mariash@pivotallabs.com>