audio_settings script can fail due to pacmd error

Sometimes the audio_before_suspend test fails with the following error:

Daemon not responding. Traceback (most recent call last): File "/usr/share/checkbox/scripts/audio_settings", line 240, in <module> sys.exit(main()) File "/usr/share/checkbox/scripts/audio_settings", line 217, in main store_audio_settings(args.file) File "/usr/share/checkbox/scripts/audio_settings", line 90, in store_audio_settings universal_newlines=True) File "/usr/lib/python3.2/subprocess.py", line 522, in check_output raise CalledProcessError(retcode, cmd, output=output) subprocess.CalledProcessError: Command '['pacmd', 'list-sources']' returned non-zero exit status 1

It seems that if the audio_settings script is run at the wrong moment, then 'pacmd list-sources' can give an error code, causing this crash. This is not very easily reproducible but may be due to the point at which the script runs.