fixed authenticator to wait only once

issue #1

certbot_pdns/PdnsApiAuthenticator.py

         self.flush_zone(zone["name"])
         self.notify_zone(zone["name"])
 
+        return response
+
+    def wait_for_propagation(self, achalls):
+        # TODO search zones authoritative servers and check for TXT record on each of them
         # raw_input('Press <ENTER> to continue')
         logger.info("Waiting %i seconds..." % self.axfr_time)
         time.sleep(self.axfr_time)
 
-        return response
-
     def cleanup(self, achall):
         domain = achall.domain
         zone = self.find_best_matching_zone(domain)

certbot_pdns/authenticator.py

         pass
 
     def perform(self, achalls):  # pylint: disable=missing-docstring
-        return [self._perform_single(achall) for achall in achalls]
+        responses = [self._perform_single(achall) for achall in achalls]
+        self.backend.wait_for_propagation(achalls)
+        return responses
 
     def _perform_single(self, achall):
         response, validation = achall.response_and_validation()