log err.error() if ConnectRetry is enabled

[tvojacek]

If ConnectRetry is enabled and connection fail, it is hard to determine root cause of failure.
This is change will print error to log.

[MattBrittan]

Thanks for the contribution; unfortunately I cannot accept it without a signed ECA (this ensures that contributions are appropriately licenced; I realise this seems like overkill for such a small change but unfortunately its a requirement for any change).

[tvojacek]

Thanks for the contribution; unfortunately I cannot accept it without a signed ECA (this ensures that contributions are appropriately licenced; I realise this seems like overkill for such a small change but unfortunately its a requirement for any change).

ECA signed