"Added music" multimedia test fails if XDG_MUSIC_DIR does not start $HOME

[David]

Steps to reproduce:

 * Running Accomplishments 0.3~precise2 from stable PPA
 * Set XDG_MUSIC_DIR to any path not starting with $HOME (e.g. /home/shared/Music as opposed to $HOME/Music)
 * Wait for "Added music" test to run

What should happen:

 * Test runs against alternate folder

What happens instead:

2013-11-23 12:23:48+0200 [-] Running ubuntu-desktop/multimedia-added-music, left on queue: 14
2013-11-23 12:23:48+0200 [-] 'Got non-zero exit code for process: '
2013-11-23 12:23:48+0200 [-] Traceback (most recent call last):
   File "/usr/share/accomplishments/scripts/ubuntu-desktop/multimedia/multimedia-added-music.py", line 33, in <module>
     test_for_music(music)
   File "/usr/share/accomplishments/scripts/ubuntu-desktop/multimedia/multimedia-added-music.py", line 16, in test_for_music
     dirList = os.listdir(directory)
 OSError: [Errno 2] No such file or directory: '/home/username/shared/Music'

[David (lofidevops)]

The test in this PPA matches the latest from the code repository. The following change stopped the bug, and allowed me to earn the trophy:

...

if musicDir[15:20] == "$HOME":
    # generate home-based path
    music = os.path.join(homedir, musicDir[21:-2])
else:
    # extract non-home-based path
    music = musicDir[15:-2]

# test valid path for music
if os.path.isdir(music):
    test_for_music(music)

#user has no music
sys.exit(1)