Use correct redis service name on Ubuntu

Fixes ansible-tower service failure when [re]starting on Ubuntu systems.

Trello: https://trello.com/c/YLZM5SUH

tools/scripts/ansible-tower

@@ -18,7 +18,7 @@
 
 if [ -e /etc/debian_version ]
 then
-    SERVICES=(postgresql redis apache2 supervisor)
+    SERVICES=(postgresql redis-server apache2 supervisor)
 else
     SERVICES=(postgresql redis httpd supervisord)
 fi