Raise NotImplementedError in dns_driver.DNSDriver.

Updates dns_driver.DNSDriver so that we raise NotImplementedError
instead of returning empty result sets or passing. Since this
class is the default dns_driver for Nova it can be quite
confusing when it returns empty results (which actually
causes some HTTP 500 errors as well).

We really need to switch the default floating/instance
dns managers to MiniDNS as smoketests fail otherwise we
currently use nova.network.dns_driver.DNSDriver which is
not correct

Fixes LP Bug #1040236
Fixes LP Bug #1027998

Change-Id: Id818bb00e0689d96db948872842c07d2cf1edd57

nova/config.py

@@ -182,13 +182,13 @@ def _get_my_ip():
                default='nova.cert.manager.CertManager',
                help='full class name for the Manager for cert'),
     cfg.StrOpt('instance_dns_manager',
-               default='nova.network.dns_driver.DNSDriver',
+               default='nova.network.minidns.MiniDNS',
                help='full class name for the DNS Manager for instance IPs'),
     cfg.StrOpt('instance_dns_domain',
                default='',
                help='full class name for the DNS Zone for instance IPs'),
     cfg.StrOpt('floating_ip_dns_manager',
-               default='nova.network.dns_driver.DNSDriver',
+               default='nova.network.minidns.MiniDNS',
                help='full class name for the DNS Manager for floating IPs'),
     cfg.StrOpt('network_manager',
                default='nova.network.manager.VlanManager',

nova/network/dns_driver.py

@@ -20,25 +20,25 @@ def __init__(self):
         pass
 
     def get_domains(self):
-        return []
+        raise NotImplementedError()
 
     def create_entry(self, _name, _address, _type, _domain):
-        pass
+        raise NotImplementedError()
 
     def delete_entry(self, _name, _domain):
-        pass
+        raise NotImplementedError()
 
     def modify_address(self, _name, _address, _domain):
-        pass
+        raise NotImplementedError()
 
     def get_entries_by_address(self, _address, _domain):
-        return []
+        raise NotImplementedError()
 
     def get_entries_by_name(self, _name, _domain):
-        return []
+        raise NotImplementedError()
 
     def create_domain(self, _fqdomain):
-        pass
+        raise NotImplementedError()
 
     def delete_domain(self, _fqdomain):
-        pass
+        raise NotImplementedError()