Improve comment about init routines

backend/app.py

@@ -95,12 +95,10 @@ def init_routines():
         # Same for the list of oauthclients.
         cluster_config.populate_oauthclients()
 
-# `init_routines` has to run only once per dashboard instance, or at least not
-# concurrently. We used to have locking in place to prevent concurrent
-# executions of this code, but we now rely on proper configuration of gunicorn
-# and/or flask to make sure this is run only once. In particular:
+# `init_routines`should only run once per dashboard instance. To enforce this we
+# have a different mode for production and development mode:
 # * we have "preload" on for gunicorn, so this file is loaded only once, before
-#   workers are forked;
+#   workers are forked (production);
 # * we make sure that in development mode we run this only once, even though
 #   this file is loaded twice by flask for some reason.
 if DEV_MODE: