Don't segfault on fail to create drm factory

    sp<IDrmFactory> factory = IDrmFactory::getService("drm");

    if (factory == NULL) {

        ALOGE("Failed to make drm factory");

        return NULL;

    }

    ALOGD("makeDrmFactory: service is %s",

            factory->isRemote() ? "Remote" : "Not Remote");

    return factory;

}