doc/install: remove reference to "Go Tutorial"

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5841054

doc/install.html

@@ -200,8 +200,7 @@ If you see the "hello, world" message then your Go installation is working.
 <h2 id="next">What's next</h2>
 
 <p>
-Start by taking <a href="http://code.google.com/p/go-tour/">A Tour of Go</a>
-or reading the <a href="/doc/go_tutorial.html">Go Tutorial</a>.
+Start by taking <a href="http://code.google.com/p/go-tour/">A Tour of Go</a>.
 </p>
 
 <p>