Add the missing option to the wget command for updating Docker.

Signed-off-by: Raghuram Devarakonda <draghuram@gmail.com>

docs/sources/installation/ubuntulinux.md

@@ -302,5 +302,5 @@ NetworkManager (this might slow your network).
 
 To install the latest version of Docker, use the standard `-N` flag with `wget`:
 
-	$ wget -N https://get.docker.com/ | sh
+	$ wget -N -qO- https://get.docker.com/ | sh