Tested on 1.8.1: b74ea963cefffad9fbd91d4eb9b240f6a8c86cd0
OS: Ubuntu 15.04, Fedora 22

Steps:
1. Open toaster.
2. Create project & build an image (core-image-minimal)
3. Once image finishes, go to build summary page and try to download any artifact resulted from the build, or the build log.

Expected:
Download begins.

Observed:
Toaster throws up an error page.

Error log:
Environment:


Request Method: GET
Request URL: http://localhost:8000/toastergui/build/2/artifact/imagefile/id/5

Django Version: 1.6
Python Version: 2.7.9
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.messages',
 'django.contrib.sessions',
 'django.contrib.admin',
 'django.contrib.staticfiles',
 'django.contrib.humanize',
 'orm',
 'toastermain',
 'south',
 'bldcontrol',
 'bldviewer',
 'toastergui')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Traceback:
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response
  114.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/dave/FP_1.8.1/poky/bitbake/lib/toaster/toastergui/views.py" in build_artifact
  3196.             return _get_be_artifact(request, build_id, artifact_type, artifact_id)
File "/home/dave/FP_1.8.1/poky/bitbake/lib/toaster/toastergui/views.py" in _get_be_artifact
  3212.                 content_type = b.buildrequest.environment.get_artifact_type(file_name)
File "/home/dave/FP_1.8.1/poky/bitbake/lib/toaster/bldcontrol/models.py" in get_artifact_type
  59.                     m = magic.Magic(magic.MAGIC_MIME)
File "/usr/local/lib/python2.7/dist-packages/magic/identify.py" in __init__
  66.         pathstr = b':'.join(iter_encode(paths)) if paths else None
File "/usr/local/lib/python2.7/dist-packages/magic/compatability.py" in iter_encode
  40.     for item in iterable:

Exception Type: TypeError at /toastergui/build/2/artifact/imagefile/id/5
Exception Value: 'int' object is not iterable