chore(requirements): update Django to v1.11.4

See https://docs.djangoproject.com/en/1.11/releases/1.11.4/

Author: mboersma

rootfs/requirements.txt

@@ -1,6 +1,6 @@
 # Deis controller requirements
 backoff==1.4.3
-Django==1.11.3
+Django==1.11.4
 django-auth-ldap==1.2.14
 django-cors-middleware==1.3.1
 django-guardian==1.4.9