rate limiter: disable based on if remote ip was found, not on if the plug was enabled

The current rate limiter disable logic won't trigger when the remote ip is not forwarded, only when the remoteip plug is not enabled, which is not the case on most instances since it's enabled by default. This changes the behavior to warn and disable when the remote ip was not forwarded, even if the RemoteIP plug is enabled.

Also closes #1620 (closed)