preflight: Assume old iOS version if retrieval of ProductVersion fails

Some older devices (e.g. iOS 2.x) wouldn't allow querying the iOS version
if the device is not paired. In this case we just assume an old version
instead of erroring out, and this way the device will be made available.

src/preflight.c

@@ -214,18 +214,19 @@ static void* preflight_worker_handle_device_add(void* userdata)
 
 	lerr = lockdownd_get_value(lockdown, NULL, "ProductVersion", &value);
 	if (lerr != LOCKDOWN_E_SUCCESS) {
-		usbmuxd_log(LL_ERROR, "%s: ERROR: Could not get ProductVersion from device %s, lockdown error %d", __func__, _dev->udid, lerr);
-		goto leave;
-	}
-
-	if (value && plist_get_node_type(value) == PLIST_STRING) {
-		plist_get_string_val(value, &version_str);
-	}
-	plist_free(value);
+		usbmuxd_log(LL_WARNING, "%s: Could not get ProductVersion from device %s, lockdown error %d", __func__, _dev->udid, lerr);
+		/* assume old iOS version */
+		version_str = strdup("1.0");
+	} else {
+		if (value && plist_get_node_type(value) == PLIST_STRING) {
+			plist_get_string_val(value, &version_str);
+		}
+		plist_free(value);
 
-	if (!version_str) {
-		usbmuxd_log(LL_ERROR, "%s: Could not get ProductVersion string from device %s handle %d", __func__, _dev->udid, (int)(long)_dev->conn_data);
-		goto leave;
+		if (!version_str) {
+			usbmuxd_log(LL_ERROR, "%s: Could not get ProductVersion string from device %s handle %d", __func__, _dev->udid, (int)(long)_dev->conn_data);
+			goto leave;
+		}
 	}
 
 	lerr = lockdownd_get_value(lockdown, NULL, "DeviceClass", &value);