google: fix typo

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)

docs/sources/installation/google.md

@@ -28,7 +28,7 @@ page_keywords: Docker, Docker documentation, installation, google, Google Comput
 4. Connect to the instance using SSH:
 
         $ gcloud compute ssh --zone us-central1-a docker-playground
-        $$ docker-playground:~$ sudo docker run hello-world
+        docker-playground:~$ sudo docker run hello-world
 	Hello from Docker.
 	This message shows that your installation appears to be working correctly.
 	...