Move all V2 Controllers to inherit from the v2

Previously some v2 controllers inherited from the base
client.Controller.

Fixes have been added to the V2Controller that allow it
to work with lists + next links.

Change-Id: I23b4ecc52b71cafc4085ab6586164bd03ac6afea

designateclient/v2/base.py

@@ -40,4 +40,4 @@ class V2Controller(client.Controller):
 
             return data
 
-        return body
+        return body

designateclient/v2/blacklists.py

@@ -13,10 +13,10 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from designateclient import client
+from designateclient.v2.base import V2Controller
 
 
-class BlacklistController(client.Controller):
+class BlacklistController(V2Controller):
     def create(self, pattern, description=None):
         data = {
             'pattern': pattern,

designateclient/v2/limits.py

@@ -13,9 +13,9 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from designateclient import client
+from designateclient.v2.base import V2Controller
 
 
-class LimitController(client.Controller):
+class LimitController(V2Controller):
     def get(self):
         return self._get('/limits')

designateclient/v2/nameservers.py

@@ -13,11 +13,11 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from designateclient import client
+from designateclient.v2.base import V2Controller
 from designateclient.v2 import utils as v2_utils
 
 
-class NameServerController(client.Controller):
+class NameServerController(V2Controller):
     def list(self, zone):
         zone = v2_utils.resolve_by_name(self.client.zones.list, zone)
 

designateclient/v2/reverse.py

@@ -13,10 +13,10 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from designateclient import client
+from designateclient.v2.base import V2Controller
 
 
-class FloatingIPController(client.Controller):
+class FloatingIPController(V2Controller):
     def set(self, floatingip_id, ptrdname, description=None, ttl=None):
         data = {
             'ptrdname': ptrdname