Fix Database Url check, force mailman to start, remove security settings in

django.

- -z Does not check properly if the DATABASE_URL is defined or not. It evaluates
   to True if it is not set or set to ''

- Remove SECURE_SSL_REDIRECT in the django settings because this deployment is
  meant to behind Nginx which decrypts SSL packets.

- Force mailman to start even with a lock. This _may_ not be the best idea but
  for now if everything is followed according to this guide.

web/mailman-web/settings.py

@@ -162,13 +162,6 @@ USE_X_FORWARDED_HOST = True
 # SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_SCHEME', 'https')
 
 # Other security settings
-SECURE_SSL_REDIRECT = True
-# If you set SECURE_SSL_REDIRECT to True, make sure the SECURE_REDIRECT_EXEMPT
-# contains at least this line:
-SECURE_REDIRECT_EXEMPT = [
-    # Request from Mailman.
-    "archives/api/mailman/.*",
-     ]
 # SESSION_COOKIE_SECURE = True
 # SECURE_CONTENT_TYPE_NOSNIFF = True
 # SECURE_BROWSER_XSS_FILTER = True