Call the callback on connectStream socket creation failure.

The callback must *always* be called at some point, because the generic async->sync logic in vibe-core otherwise has no way to know whether to expect a callback or not.

source/eventcore/driver.d

@@ -570,6 +570,7 @@ enum ConnectStatus {
 	refused,
 	timeout,
 	bindFailure,
+	socketCreateFailure,
 	unknownError
 }