Fix deprecation warnings for Django 1.11 and Django 2.0.

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

mayan/apps/document_indexing/views.py

@@ -1,8 +1,8 @@
 from __future__ import absolute_import, unicode_literals
 
 from django.contrib import messages
-from django.core.urlresolvers import reverse, reverse_lazy
 from django.shortcuts import get_object_or_404
+from django.urls import reverse, reverse_lazy
 from django.utils.html import mark_safe
 from django.utils.translation import ugettext_lazy as _