Revert "FIX: allow CURLOPT_CONNECTTIMEOUT to be configured."

Basically, we shouldn't be creating individual setters and getters for each curl option. Instead they should be set using the curlOptions array or default config.

```php
Config::inst()->update('RestfulService', 'default_curl_options', array(
    CURLOPT_CONNECTTIMEOUT => 10
));
```

This reverts commit 0d493d4effb8994480976dee7042c498f2057df9.

See https://github.com/silverstripe/silverstripe-framework/pull/2699#issuecomment-41789220

cc @chillu