Make sure default vars are used in template calls for tasks

Fixes #8499

lib/ansible/playbook/task.py

@@ -208,11 +208,15 @@ class Task(object):
         self.changed_when = ds.get('changed_when', None)
         self.failed_when = ds.get('failed_when', None)
 
+        # combine the default and module vars here for use in templating
+        all_vars = self.default_vars.copy()
+        all_vars = utils.combine_vars(all_vars, self.module_vars)
+
         self.async_seconds = ds.get('async', 0)  # not async by default
-        self.async_seconds = template.template_from_string(play.basedir, self.async_seconds, self.module_vars)
+        self.async_seconds = template.template_from_string(play.basedir, self.async_seconds, all_vars)
         self.async_seconds = int(self.async_seconds)
         self.async_poll_interval = ds.get('poll', 10)  # default poll = 10 seconds
-        self.async_poll_interval = template.template_from_string(play.basedir, self.async_poll_interval, self.module_vars)
+        self.async_poll_interval = template.template_from_string(play.basedir, self.async_poll_interval, all_vars)
         self.async_poll_interval = int(self.async_poll_interval)
         self.notify = ds.get('notify', [])
         self.first_available_file = ds.get('first_available_file', None)