smtp->send: Allowing ssl when using an external host

Allowing ssl when OpenSSL is not loaded/available on the PHP server but we don't mind as we are using another host (like smtp.gmail.com not to mention it)

**UPDATE**: 
`stream_socket_enable_crypto` needs it, but it's then related to the TLS scheme. Should we then put `!extension_loaded('openssl')` line 158?

```php 
if (strtolower($this->scheme)=='tls' && extension_loaded('openssl'))`  + `else return FALSE;
```