Change Django's configuration preference in manage.py

Signed-off-by: Giovanni Cimolin da Silva <giovannicimolin@gmail.com>

manage.py

@@ -97,11 +97,13 @@ def parse_args():
 if __name__ == "__main__":
     edx_args, django_args = parse_args()
 
+    edx_args_base = edx_args.settings_base.replace('/', '.') + '.'
     if edx_args.settings:
-        os.environ["DJANGO_SETTINGS_MODULE"] = edx_args.settings_base.replace('/', '.') + "." + edx_args.settings
-    else:
-        os.environ.setdefault("DJANGO_SETTINGS_MODULE", edx_args.default_settings)
+        os.environ["DJANGO_SETTINGS_MODULE"] = edx_args_base + edx_args.settings
+    elif os.environ.get("EDX_PLATFORM_SETTINGS") and not os.environ.get("DJANGO_SETTINGS_MODULE"):
+        os.environ["DJANGO_SETTINGS_MODULE"] = edx_args_base + os.environ["EDX_PLATFORM_SETTINGS"]
 
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", edx_args.default_settings)
     os.environ.setdefault("SERVICE_VARIANT", edx_args.service_variant)
 
     enable_contracts = os.environ.get('ENABLE_CONTRACTS', False)