Set correct DNS after reverting 'hardware' snapshot

In case an environemnt already exists, tests are
reverting its 'hardware' snapshot before deploying
k8s. Need to set proper DNS in config after that.

Change-Id: I56df3c211a91ab79c21a25674f36aad55126d5a9

fuel_ccp_tests/managers/envmanager_devops.py

@@ -60,6 +60,7 @@ class EnvironmentManager(object):
         except error.DevopsObjNotFound:
             LOG.info("Environment doesn't exist, creating a new one")
             self._create_environment()
+        self.set_dns_config()
 
     @property
     def _devops_config(self):
@@ -245,7 +246,6 @@ class EnvironmentManager(object):
             )
             raise exceptions.EnvironmentAlreadyExists(env_name)
         self._env.define()
-        self.set_dns_config()
         LOG.info(
             'Environment "{0}" created and started'.format(env_name)
         )