Change when 'has-jobs-<>' cache key gets set

We should set the cache after the job has been created, in case there
was an HTTP error when creating the job.

app/notify_client/job_api_client.py

@@ -97,12 +97,6 @@ class JobApiClient(NotifyAdminAPIClient):
         return bool(self.get_jobs(service_id)['data'])
 
     def create_job(self, job_id, service_id, scheduled_for=None):
-        redis_client.set(
-            'has_jobs-{}'.format(service_id),
-            b'true',
-            ex=cache.TTL,
-        )
-
         data = {"id": job_id}
 
         if scheduled_for:
@@ -111,6 +105,12 @@ class JobApiClient(NotifyAdminAPIClient):
         data = _attach_current_user(data)
         job = self.post(url='/service/{}/job'.format(service_id), data=data)
 
+        redis_client.set(
+            'has_jobs-{}'.format(service_id),
+            b'true',
+            ex=cache.TTL,
+        )
+
         stats = self.__convert_statistics(job['data'])
         job['data']['notifications_sent'] = stats['delivered'] + stats['failed']
         job['data']['notifications_delivered'] = stats['delivered']