Add sudo clause if your using osx or tcp

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

docs/sources/examples/example_header.inc

@@ -4,4 +4,5 @@
     * This example assumes you have Docker running in daemon mode. For
       more information please see :ref:`running_examples`.
     * **If you don't like sudo** then see :ref:`dockergroup`
+    * **If you're using OS X or docker via TCP** then you shouldn't use `sudo`