Update prebuilts to go1.7 ab/3151923

toolchain/go sha a31456e050

Change-Id: I21a58e6f1f449ccafc2a66a7ae64a8fdb2fd66f9
diff --git a/doc/install-source.html b/doc/install-source.html
index 991be3f..11c66ad 100644
--- a/doc/install-source.html
+++ b/doc/install-source.html
@@ -203,7 +203,7 @@
 Change to the directory that will be its parent
 and make sure the <code>go</code> directory does not exist.
 Then clone the repository and check out the latest release tag
-(<code class="versionTag">go1.6</code>, for example):</p>
+(<code class="versionTag">go1.7</code>, for example):</p>
 
 <pre>
 $ git clone https://go.googlesource.com/go
@@ -391,7 +391,7 @@
 <a href="//groups.google.com/group/golang-announce">golang-announce</a>
 mailing list.
 Each announcement mentions the latest release tag, for instance,
-<code class="versionTag">go1.6</code>.
+<code class="versionTag">go1.7</code>.
 </p>
 
 <p>