grizzly: Allow multiple dns servers when starting dnsmasq

[Tom Fifield]

https://review.openstack.org/21444 added a new configuration option and enhanced a feature in nova: Allow multiple dns servers when starting dnsmasq

    Previously we only allowed one upstream dns server even though we
    can store two in the network object. This changes the dns_server
    flag to a MultiStrOpt so it can be specified multiple times.

    It also adds a new config 'use_network_dns_servers' which specifies
    to uses the dns servers from the network if they are set. This
    defaults to false to ensure configs do not need to be changed.

Changed default option and text:
 64 cfg.MultiStrOpt('dns_server',
65 default=[],
66 help='if set, uses specific dns server for dnsmasq. Can'
   67 'be specified multiple times.'),

New option:
   68 cfg.BoolOpt('use_network_dns_servers',
   69 default=False,
   70 help='if set, uses the dns1 and dns2 from the network ref.'
   71 'as dns servers.'),

[Tom Fifield (fifieldt)]

https://review.openstack.org/22165