Downloading the files(which are uploaded) from media folder in django 1.4.3

I am using django to design the basic web pages that handles the uploading and downloading of the files to/from the media folder

Actually the files are uploaded successfully in to the media folder, also files are downloaded successfully but an underscore is appended to the file_name as a last charater like file_one.pdf_ , file_two.pdf_ , file_three.txt_ etc.,

Below are my codes

urls.py

urlpatterns = patterns('',
             url(r'^upload$', 'learn_django.views.upload'),
             url(r'^files_list$', 'learn_django.views.files_list'),
             url(r'^download/(?P<file_name>.+)$', 'learn_django.views.download'),
)
if settings.DEBUG:
    urlpatterns = patterns('',
    url(r'^media/(?P<path>.*)$', 'django.views.static.serve',{'document_root': settings.MEDIA_ROOT, 'show_indexes': True}),
) + urlpatterns

views.py

def upload(request):
    ......
    ....
    return render_to_response('uploads_form.html', {'form': form},context_instance=RequestContext(request))


def files_list(request):
    return render_to_response('files_list.html',{'total_files':os.listdir(settings.MEDIA_ROOT),'path':settings.MEDIA_ROOT},context_instance=RequestContext(request))

def download(request,file_name):
    file_path = settings.MEDIA_ROOT +'/'+ file_name
    file_wrapper = FileWrapper(file(file_path,'rb'))
    file_mimetype = mimetypes.guess_type(file_path)
    response = HttpResponse(file_wrapper, content_type=file_mimetype )
    response['X-Sendfile'] = file_path
    response['Content-Length'] = os.stat(file_path).st_size
    response['Content-Disposition'] = 'attachment; filename=%s/' % smart_str(file_name) 
    return response

files_list.html

<table border="1" colspan="2" width="100%">
   <tr>