'SSLEngine closed already' exception on failed outbound connection

Occasionally Netty will invoke OutboundConnectionInitiator#exceptionCaught() handler to process an exception of the following kind:

io.netty.channel.unix.Errors$NativeIoException: readAddress(..) failed: Connection reset by peer

When we invoke ctx.close() later in that method, the listener, set up in channelActive(), might be
failed with an SSLException("SSLEngine closed already”) by Netty, and exceptionCaught() will be invoked
once again, this time to handle the SSLException triggered by ctx.close().

The exception at this stage is benign, and we shouldn't be double-logging the failure to connect.