Update to the latest beat.core changes

beat/web/backend/models.py

@@ -1422,8 +1422,9 @@ class JobSplit(models.Model):
                 JobSplit.host = Host(images_cache=docker_images_cache)
                 JobSplit.host.setup(raise_on_errors=not(getattr(settings, 'TEST_CONFIGURATION', False)))
 
-            self.executor = beat.core.execution.Executor(JobSplit.host, settings.PREFIX, config,
-                cache)
+            self.executor = beat.core.execution.DockerExecutor(
+                JobSplit.host, settings.PREFIX, config, cache
+            )
 
             if not self.executor.valid:
                 err = ''