Security update for python-Django

Open Source Vulnerabilities openSUSE-SU-2018:2327-1

This update for python-Django to 1.11.15 fixes the following issues: This security issue was fixed: - CVE-2018-14574: Prevent open redirect in django.middleware.common.CommonMiddleware (bsc#1102680). These non-security issues were fixed: - Fixed WKBWriter.write() and write_hex() for empty polygons on GEOS 3.6.1+ - Fixed a regression that could result in large memory usage when making edits using ModelAdmin.list_editable - Fixed a regression where QuerySet.values() or values_list() after combining an annotated and unannotated queryset with union(), difference(), or intersection() crashed due to mismatching columns - Fixed crashes in django.contrib.admindocs when a view is a callable object, such as django.contrib.syndication.views.Feed - Fixed a regression where altering a field with a unique constraint may drop and rebuild more foreign keys than necessary - Fixed a regression where combining two annotated values_list() querysets with union(), difference(), or intersection() crashed due to mismatching columns - Fixed a regression where an empty choice could be initially selected for the SelectMultiple and CheckboxSelectMultiple widgets