[tests] Fixed warning due to a stupid mixup of void/char.
[tests] Fixed warning due to a stupid mixup of void/char.

deniskropp/DirectFB,lancebaiyouview/DirectFB,djbclark/directfb-core-DirectFB,Distrotech/DirectFB,deniskropp/DirectFB,sklnet/DirectFB,deniskropp/DirectFB,lancebaiyouview/DirectFB,dfbdok/DirectFB1,kevleyski/directfb,kevleyski/directfb,kaostao/directfb,kevleyski/DirectFB-1,dfbdok/DirectFB1,mtsekm/test,dfbdok/DirectFB1,deniskropp/DirectFB,DirectFB/directfb,djbclark/directfb-core-DirectFB,kevleyski/DirectFB-1,DirectFB/directfb,Distrotech/DirectFB,djbclark/directfb-core-DirectFB,sklnet/DirectFB,jcdubois/DirectFB,mtsekm/test,jcdubois/DirectFB,jcdubois/DirectFB,sklnet/DirectFB,kaostao/directfb,kaostao/directfb,kevleyski/directfb,DirectFB/directfb,Distrotech/DirectFB,lancebaiyouview/DirectFB,djbclark/directfb-core-DirectFB,sklnet/DirectFB,kevleyski/DirectFB-1,mtsekm/test,kevleyski/directfb,kevleyski/DirectFB-1,lancebaiyouview/DirectFB