Add TIMEOUT in the list of allowed config paramaters, make sure no random memory is parted for potential options and fix output when the parameters name entered is invalid

[mochouinard]

Add TIMEOUT in the list of allowed config paramaters, make sure no random memory is parted for potential options and fix output when the parameters name entered is invalid.

Note that the timeout error output would still show (10) even if a different timeout is set.

[mochouinard]

The reason for this change, is because if my DNS server is not responding, EXIM4 take more than 10 second to timeout before answering on port 25. Even if Internet is down, I want my email to be queued by the local agent