Honor trash_output when not using queue

Previously, trash_output was not honored if a queue was not being used
to post messages.

This patch changes the behavior so that trash_output will be honored
even if a queue is not being used, and all stdout/stderr will be
discarded.

Change-Id: I4fccfa0cb2a5382a52d63598f66dae446ff29c25
Closes-Bug: #1842102

releasenotes/notes/honor_trash_output_when_not_using_queue-f7c5a3051f5b90cc.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - Previously, trash_output was not honored if a queue was not being used to
+    post messages.  The behavior has changed so that trash_output will be
+    honored even if a queue is not being used, and all stdout/stderr will be
+    discarded.

tripleo_common/actions/ansible.py

@@ -640,6 +640,9 @@ class AnsiblePlaybookAction(base.TripleOAction):
                 *command, cwd=self.work_dir,
                 env_variables=env_variables,
                 log_errors=processutils.LogErrors.ALL)
+            if self.trash_output:
+                stdout = ""
+                stderr = ""
             return {"stderr": stderr, "stdout": stdout,
                     "log_path": os.path.join(self.work_dir, 'ansible.log')}
         finally: