Fix deprecation warnings for Django 1.11 and Django 2.0.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/folders/models.py

@@ -1,7 +1,7 @@
 from __future__ import absolute_import, unicode_literals
 
-from django.core.urlresolvers import reverse
 from django.db import models
+from django.urls import reverse
 from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 

mayan/apps/folders/tests/test_api.py

@@ -1,8 +1,8 @@
 from __future__ import unicode_literals
 
 from django.contrib.auth import get_user_model
-from django.core.urlresolvers import reverse
 from django.test import override_settings
+from django.urls import reverse
 
 from documents.models import DocumentType
 from documents.tests import TEST_DOCUMENT_TYPE, TEST_SMALL_DOCUMENT_PATH

mayan/apps/folders/views.py

@@ -3,8 +3,8 @@ from __future__ import absolute_import, unicode_literals
 import logging
 
 from django.contrib import messages
-from django.core.urlresolvers import reverse_lazy
 from django.shortcuts import get_object_or_404
+from django.urls import reverse_lazy
 from django.utils.translation import ugettext_lazy as _, ungettext
 
 from acls.models import AccessControlList