Remove unreferenced mustache_helpers code

I can't seem to find any references to this code outside of the library
and the tests themselves.

lms/djangoapps/django_comment_client/mustache_helpers.py

-from django.utils.translation import ugettext as _
-import django.core.urlresolvers as urlresolvers
-import sys
-import inspect
-
-# This method is used to pluralize the words "discussion" and "comment"
-# which is why you need to tack on an "s" for the case of 0 or two or more.
-
-
-def pluralize(content, text):
-    num, word = text.split(' ')
-    num = int(num or '0')
-    if num >= 2 or num == 0:
-        return word + 's'
-    else:
-        return word
-
-
-def url_for_user(content, user_id):
-    return urlresolvers.reverse('django_comment_client.forum.views.user_profile', args=[content['course_id'], user_id])
-
-
-def close_thread_text(content):
-    if content.get('closed'):
-        return _('Re-open thread')
-    else:
-        return _('Close thread')
-
-current_module = sys.modules[__name__]
-all_functions = inspect.getmembers(current_module, inspect.isfunction)
-
-mustache_helpers = {k: v for k, v in all_functions if not k.startswith('_')}

lms/djangoapps/django_comment_client/tests/test_mustache_helpers.py

-from django.test import TestCase
-import django_comment_client.mustache_helpers as mustache_helpers
-
-
-class PluralizeTest(TestCase):
-    def setUp(self):
-        super(PluralizeTest, self).setUp()
-        self.text1 = '0 goat'
-        self.text2 = '1 goat'
-        self.text3 = '7 goat'
-        self.content = 'unused argument'
-
-    def test_pluralize(self):
-        self.assertEqual(mustache_helpers.pluralize(self.content, self.text1), 'goats')
-        self.assertEqual(mustache_helpers.pluralize(self.content, self.text2), 'goat')
-        self.assertEqual(mustache_helpers.pluralize(self.content, self.text3), 'goats')
-
-
-class CloseThreadTextTest(TestCase):
-    def setUp(self):
-        super(CloseThreadTextTest, self).setUp()
-        self.contentClosed = {'closed': True}
-        self.contentOpen = {'closed': False}
-
-    def test_close_thread_text(self):
-        self.assertEqual(mustache_helpers.close_thread_text(self.contentClosed), 'Re-open thread')
-        self.assertEqual(mustache_helpers.close_thread_text(self.contentOpen), 'Close thread')