doc: GCC 4.8.1 is not updated to Go 1.1

I will try again for 4.8.2.

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/9663045

doc/go1.1.html

@@ -159,7 +159,7 @@ The GCC release schedule does not coincide with the Go release schedule, so some
 <code>gccgo</code>'s releases.
 The 4.8.0 version of GCC shipped in March, 2013 and includes a nearly-Go 1.1 version of <code>gccgo</code>.
 Its library is a little behind the release, but the biggest difference is that method values are not implemented.
-Sometime around May 2013, we expect 4.8.1 of GCC to ship with a <code>gccgo</code>
+Sometime around July 2013, we expect 4.8.2 of GCC to ship with a <code>gccgo</code>
 providing a complete Go 1.1 implementaiton.
 </p>