production.ini.example: comment out sentry_dsn

This will break an install if people copy this file and don't set or
remove this, so it should probably be commented out by default and let
people un-comment if they actually want to use it.

tildes/production.ini.example

@@ -18,8 +18,8 @@ redis.sessions.timeout_trigger = 0
 # set session timeout to 1 hour by default, we'll extend it when people log in
 redis.sessions.timeout = 3600
 
-# this should only be set if you have a Sentry instance you want to send errors to
-sentry_dsn = https://key@sentry.io/project
+# uncomment and set this if you have a Sentry instance you want to send errors to
+# sentry_dsn = https://key@sentry.io/project
 
 sqlalchemy.url = postgresql+psycopg2://tildes:@:6432/tildes