Update migration-pp-to-ppr.md

Author: eshashah-msft

articles/iot-hub-device-update/migration-pp-to-ppr.md

@@ -32,7 +32,7 @@ For the Public Preview Refresh release, the Device Update agent needs to be upda
 
 4. Remove the old configuration file
    ```bash
-   rm -f /etc/adu/adu-conf.txt 
+   sudo rm -f /etc/adu/adu-conf.txt 
    ```
 
 5. Install the new agent