Merge "adb shouldn't trace unless told to"

}

void adb_trace_init(char** argv) {

    // Don't open log file if no tracing, since this will block

    // the crypto unmount of /data

    const std::string trace_setting = get_trace_setting();

    if (trace_setting.empty()) {

        return;

    }

#if !ADB_HOST

    if (isatty(STDOUT_FILENO) == 0) {

        start_device_log();