Manual Ubuntu upgrade - Clarify instructions

Provides a little more context around deleting the package file

content/tutorials/manage-the-rippled-server/installation/update-rippled-manually-on-ubuntu.md

@@ -28,6 +28,8 @@ To update manually, complete the following steps:
 
         $ sudo service rippled restart
 
-7. Remove the downloaded `rippled` package
+7. Delete the downloaded `rippled` package file:
         
         $ rm rippled*.rpm
+        
+    (This does not affect the installation, but prevents later updates from trying to re-install the old version.)