fix travis compile bug
fix travis compile bug

hal3/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,deaktator/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,deaktator/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,deaktator/vowpal_wabbit,deaktator/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,deaktator/vowpal_wabbit,deaktator/vowpal_wabbit,hal3/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,hal3/vowpal_wabbit