update django files to Django 2

manage.py

@@ -1,10 +1,21 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
 import os
 import sys
 
-if __name__ == "__main__":
-    os.environ["DJANGO_SETTINGS_MODULE"] = "webvirtcloud.settings"
-
-    from django.core.management import execute_from_command_line
 
+def main():
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'webvirtcloud.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
     execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()