mod_c2s_conn_throttle: Reduce log level from error->info Our general policy is that "error" should never be triggerable by remote entities, and that it is always about something that requires admin intervention. This satisfies neither condition. The "warn" level can be used for unexpected events/behaviour triggered by remote entities, and this could qualify. However I don't think failed auth attempts are unexpected enough. I selected "info" because it is what is also used for other notable session lifecycle events.

# Introduction

This module sends a [version query][xep0092] to clients when they
connect, and logs the response, allowing statistics of client usage to
be recorded.

Note that since this is per connection, there will be a bias towards
mobile clients on bad connections.

## Example

    info    Running Running Swift version 4.0